Introduction

Every year or so the monitor World gets excited about the release of a new model from Dell in their extremely popular UltraSharp line of screens. Each size of model tend to be refreshed every 2 years and the refresh cycles run so that we tend to get at least one new model of some sort each year. Last year we saw the arrival of a new 24" model, the U2412M which represented the update to the 24" U2410. We've now reached that time of year where we have a refresh to the 27" model. The new U2713HM is the update to the very popular U2711 which we reviewed in March 2010. Where the older model was part of their 2011 range, this will form part of their 2013 range, just a little early as is the norm. Like the 24" U2412M model last year it is expected that this new U2713HM will actually run along side its predecessor as both offer quite different features and specs and Dell see them as complementing offerings, as opposed to a straightforward replacement. Over the last few years we have seen the following changes in the UltraSharp line-up:

• 21.5" - U2211H from mid 2010, replaced by U2212HM in late 2011

• 23" - U2311H from mid 2010, replaced by U2312HM in late 2011

• 24" - U2410 released late 2009 still available. Subsequent U2412M released Aug 2011 to run along side the existing model

• 27" - U2711 released early 2010. New U2713HM released Aug 2012 and expected to run along side existing model

• 30" - U3011 released late 2010, possible update due in 2012?

The U2713HM follows a similar path to the U2412M last year. Perhaps the most significant change is the move from wide gamut CCFL backlighting to a W-LED unit. This brings about several changes as it did for the 24" range. The screen can now offer a slimmer profile and brings with it environmental and energy saving benefits. From a user experience point of view the screen now covers only a standard sRGB gamut instead of the wide gamut of the old model. The U2713HM is also a standard 8-bit model whereas its predecessor offered "10-bit" support through the use of an 8-bit+AFRC panel. We will look at these changes later on in the review in more detail and compare the two screens.

Dell's website states: "Cinema-like clarity shines on the expansive 27" Dell  UltraSharp  U2713HM monitor. Comfort settings and connectivity options help keep you productive. WQHD resolution and accurate colors out of the box: Superb clarity with 2560 x 1440 resolution and over 3.6 million pixels. Features a color gamut of more than 99-percent sRGB. Excellent comfort and usability: Full adjustability including swivel, tilt, height adjustability and pivot which lets you easily switch to portrait mode. Eco-friendly design: Compliant with the latest environmental standards and made using environmentally conscious materials."

Specifications and Features

The following table gives detailed information about the specs of the screen:

The U2713HM offers a very good range of video connections which is great to see and something which Dell have always done a good job with on their UltraSharp models. There are HDMI, Dual-link DVI-D, D-sub and DisplayPort provided for video interfaces. With the screen offering a 2560 x 1440 resolution though only the DL-DVI and DisplayPort connections can support the full resolution due to bandwidth limitations over VGA and HDMI. It is nevertheless nice to see VGA and HDMI provided for users who want to connect other devices, particularly external Blu-ray and DVD players. The digital interfaces are HDCP certified for encrypted content as well. There is also an audio out connection for connecting headphones / external speakers if you wish to take the sound from the HDMI or DisplayPort inputs. There are no integrated stereo speakers on this model although the screen is compatible with Dell's soundbar if you wish.

Above: Dell soundbar option shown

The screen comes packaged with a dual-link DVI and VGA cables which is useful although there is no DisplayPort or HDMI cable provided with the screen unfortunately, presumably due to cost saving measures. The screen has an internal power supply and so you only need a standard kettle lead (provided) to power the screen. Do make sure this is inserted firmly into the power socket as we initially thought our screen was DOA when it was incorrectly inserted. In fact it seems sometimes the screen is fussy about powering on if you've connected the video cables first. To avoid issue, connect the power cable and then the video cables afterwards. There is a 4-port USB 3.0 hub provided as well, with 2 ports on the back and 2 ports on the left hand side of the screen. The USB cable to connect back to your PC to power these ports is provided in the box. Unlike the U2711 model there is no 8-in-1 card reader on this model.

Below is a summary of the features and connections of the screen:

OSD Menu

 
Above: view of OSD operational buttons. Click for larger version

Unlike the U2711, the Dell U2713HM has pressable OSD selection buttons instead of any touch sensitive version. These are located on the right hand side of the screen and work well in practice. The OSD menu is almost identical to the 24" U2412M.

Pressing any of the 4 buttons brings up the quick launch menu, giving you quick access to preset mode selection and brightness / contrast controls. You can also select to enter into the main menu, or simply exit the quick launch menu. You can in fact personalise the two quick launch options from within the main menu should you wish to.

Within the preset modes menu there are options for standard, multimedia, movie, game, text, colour temp, sRGB and custom colour. The sRGB mode is a preset which was not available on the U2412M and is designed to emulate the sRGB space more closely than the native gamut of the screen. It also carries the factory calibration which we will test later on.

Bringing up the main menu presents you with various sub-sections down the left hand side as shown. At the top right there is a new "energy use" bar which gives you a visual indication of the power consumption at any given time. This is based on the OSD brightness setting which controls the backlight intensity, and therefore has a direct correlation to the power consumption. The brightness/contrast section is self explanatory of course. The second section for "auto adjust" is only relevant when using the analogue D-sub connection.

The input source section allows you to manually select which interface is in use. For some reason Dell haven't provided an "auto select" option like they did on the U2412M which can be useful when you have several devices connected to the screen I think.

Colour settings allows you to change a couple of settings relating to colour format and gamma, but perhaps more useful here is access to the preset colour modes.

The preset modes listed here are the same as those accessed via the quick launch menu. Note the presence of an sRGB mode which wasn't available on the U2412M model.

 

The display settings section allows you to change the monitors aspect ratio for external devices and games. There are options for wide 16:9, 4:3 and 5:4 here. You can also turn the dynamic contrast ratio control on and off in this section of the menu, if you are in a suitable preset mode where it can be activated. We will look at this later on in the review.

The other settings section has some controls over the OSD itself. The 'Energy Smart' feature can be turned on and off here as well.

The personalize section allows you to change the quick launch keys if you wish. You can change them to activate auto adjust, input selection and aspect ratio if you wish.

You can access the monitors factory menu as well but be careful not to change anything without knowing what you've done or how to change it back. Use the menu at your own risk! To access the factory menu, hold the top two buttons down while powering the monitor on. Once it is on, press the top button to bring up the menu. You can define the RGB levels for each of the colour temp preset modes here and there are a few other settings relating to the operation of the display.

Overall the OSD menu offers a decent range of options and it is intuitive and well structured.

 

Power Consumption

In terms of power consumption the manufacturers spec states maximum usage of 100W and typical usage of 42W. In standby the screen apparently uses <0.5W.

We tested this ourselves and found that out of the box the screen used 34.8W of power while at its default brightness setting which was 75%. At the maximum brightness setting the screen used 45.5W of power and at the lowest brightness setting, power consumption was reduced to 17.8W. After calibration the brightness had been set at 35% to achieve the desired luminance in the 'custom color' preset mode, the screen returned a power consumption of 24.8W. In standby the screen used 0.8W of power.

I have plotted the results of these measurements on the graph below:

 

Panel and Backlighting

Panel, Colour Depth and Coating

The Dell U2713HM utilises an LG.Display LM270WQ1-SLB2 AH-IPS panel which is capable of producing 16.7 million colours with a true 8-bit colour depth. Dell refer to the panel as being "AH-IPS" (Advanced High Performance IPS) in some of their marketing material, including the original Japanese press release, and it is a name which is starting to become more common in today's IPS market. We have started to see other screens emerge with these so-called AH-IPS panels in their specs, and indeed LG.Display themselves made the same distinction when discussing their forthcoming panels earlier in the year. This is the first monitor from Dell to apparently use a latest generation AH-IPS panel. This name has been used to identify super high resolution panels used in the mobile and tablet sectors (e.g. Apple "Retina" displays). However, the resolution here on the U2713HM is of course the same as it was before, being 2560 x 1440 from the 27" panel. The LM270WQ1 panel has also been around for several years now in different revisions, including those used in the Apple 27" Cinema Display, Hazro HZ27WA/C/D series and more recently in a range of other low-cost 27" IPS models from around the World. Here, Dell are using the SLB2 revision which we have not seen used elsewhere before. What makes this SLB2 revision AH-IPS as opposed to the normal H-IPS type is unclear, and in fact it is likely just a marketing name given to try and identify modern LED backlit IPS panels offering high resolutions and low energy consumption. Some people were perhaps anticipating the use of the new LM270WQ3 panel from LG.Display in this model, but that is yet to appear in the monitor market. Dell have obviously opted for a standard gamut screen as well here as they already offer the wide gamut U2711 for those who need an extended colour space.

The panel is confirmed when dismantling the screen as shown below.

You will perhaps note that the U2713HM is using the LM270WQ1 panel, whereas the older U2711 model used the LM270WQ2 panel. That was a wide gamut CCFL backlit module as opposed to using W-LED backlighting. The U2711 also offered "10-bit" support through the use of an 8-bit panel, combined with internal Frame Rate Control (8-bit + AFRC). This allowed Dell to quote a colour depth of 1.07 billion. The panel used in the U2713HM is a standard 8-bit module and so offers a 16.7m colour depth. Don't get too side-tracked with this point though as it's all very well saying a panel is capable of 10-bit colour depth (1.07 billion colour palette) as opposed to an 8-bit colour depth (16.7 million colours), but you need to take into account whether this is practically useable and whether you're ever going to truly use that colour depth. You need to have a full 10-bit end to end workflow to take advantage of it which is still quite expensive to achieve and rare in the market, certainly for your average user. Dell still provide the U2711 for those who do want or need that support of course.

The screen coating on the U2713HM is a normal anti-glare (AG) offering. This is contrary to a lot of other screens using variants of the LM270WQ1 panel which offer a glossy screen coating. Readers will be pleased to hear though that the AG coating is actually nice and light and is not the usual grainy and aggressive solution you would normally find on an IPS panel. In fact in practice it is almost what you might call a semi-gloss coating being quite similar to AU Optronics AMVA offerings. Dell seem to have toned down the AG coating which is great news. It retains its anti-glare properties to avoid unwanted reflections, but does not produce an overly grainy or dirty image that some AG coatings can.
 

Backlighting and Colour Gamut

The U2713HM uses White-LED (W-LED) backlighting producing a colour space approximately equal to the sRGB reference. This means the screen is considered a 'standard gamut' backlight type. Dell's spec suggests there is a >99% coverage of the sRGB reference space (but therefore not quite 100%), and a 72% NTSC gamut. A wide gamut screen would need to be considered by those wanting to work outside of the sRGB colour space of course and the old Dell U2711 would offer that if required.
 

PWM Flicker Tests at Various Backlight Brightness Settings

  100%                                                   50%                                                   0%

We tested the screen to establish the methods used to control backlight dimming. Our recent article talks in more details about a common method used for this which is called Pulse Width Modulation (PWM). A series of photos was taken using the method outlined in the article. These were taken at 100%, 50% and 0% brightness settings. This allows us to establish 1) whether PWM is being used to control the backlight, 2) the approximate frequency at which this operates, and 3) whether a flicker may be introduced or potentially noticeable at certain settings.

A thin white line was shown on an all-black background and a photograph was taken at a slow shutter speed of 1/8 second (in this example) as the camera was scanned left to right in front of the screen. This produces a series of white lines which can be used to identify the frequency of the PWM and how quickly the backlight is cycled on and off. The higher this frequency, the less likely you are to see artefacts and flicker. The duty cycle (the time for which the backlight is on) is also important and the shorter the duty cycle, the more potential there is that you may see flicker. Please remember that not every user would notice a flicker from the backlight but it is something to be wary of. It is also a hard thing to quantify as it is very subjective when talking about whether a user may or may not experience the side effects. We are able to at least measure the frequency of the backlight using this method and tell you whether the duty cycle is sufficiently short at certain settings that it may introduce a flicker to those sensitive to it.

Interestingly the Dell U2713HM appears to not use PWM at all for dimming of the backlight. Even at 0% brightness there was no sign of the usual splitting of the white line that you'd expect to see in these tests. We carried out the checks at an even slower shutter speed which returned the same result. This is great news for those who are affected by flickering backlights and suffer from eye fatigue and eye strain. There are very few monitors which don't use PWM for backlight dimming although we have started to see a few more recently. The HP ZR2740w, DGM IPS-2701WPH and Samsung S27B970D springs to mind as others which do not use PWM.

 

Testing Methodology

An important thing to consider for most users is how a screen will perform out of the box and with some basic manual adjustments. Since most users won't have access to hardware colorimeter tools, it is important to understand how the screen is going to perform in terms of colour accuracy for the average user.

I restored my graphics card to default settings and disabled any previously active ICC profiles and gamma corrections. The screen was tested at default factory settings using the DVI interface, and analysed using an X-rite i1 Pro Spectrophotometer (not to be confused with the new i1 Display Pro colorimeter) combined with LaCie's Blue Eye Pro software suite. An NEC branded and customised X-rite i1 Display 2 colorimeter was also used to verify the black point and contrast ratio since the i1 Pro is less reliable at the darker end.

Targets for these tests are as follows:

• CIE Diagram - validates the colour space covered by the monitors backlighting with the black triangle representing the display

• Gamma - we aim for 2.2 which is the default for computer monitors

• Colour temperature / white point - we aim for 6500k which is the temperature of daylight

• Luminance - we aim for 120 cd/m², which is the recommended luminance for LCD monitors in normal lighting conditions

• Black depth - we aim for as low as possible to maximise shadow detail and to offer us the best contrast ratio

• Contrast ratio - we aim for as high as possible. Any dynamic contrast ratio controls are turned off here if present

• dE average / maximum - as low as possible. If DeltaE >3, the color displayed is significantly different from the theoretical one, meaning that the difference will be perceptible to the viewer. If DeltaE <2, LaCie considers the calibration a success; there remains a slight difference, but it is barely undetectable. If DeltaE < 1, the color fidelity is excellent.

 

Default Performance and Setup

Default settings of the screen were as follows:

Dell U2713HM - Default Factory Settings

   

 

The screen comes out of the box in the 'standard' preset mode, although there is an additional preset which carries a factory calibration which we will test shortly. Default setup of the screen actually felt very good to the naked eye although it was a little too bright. Colours felt even and not too cold, not too warm. Note that in the 'standard' preset mode the RGB levels are not available to change to the user.

 

Out of the box the performance of the screen was pleasing. The CIE diagram on the left confirms that the monitors colour gamut (black triangle) matches the sRGB colour space (orange triangle) reasonably closely. It extends a little past the sRGB space in some blues in particular in this 2D view of gamut. There is pretty much no under-coverage of the sRGB reference space and we know from Dell's spec that it can cover >99% of the sRGB reference which is great. There is a chance of some slight oversaturation in this preset in some shades compared with the exact sRGB colour space if you are carrying out colour critical work.

 

 

Default gamma was recorded at 2.1 average, leaving it only 3% out from the target of 2.2 which was good. White point was close to the target, being recorded at 6754k and being only 4% out and a little too cool. Note that we are using a spectrophotometer to make these measurements which is not sensitive to the W-LED backlight as some colorimeter devices can be. When using a standard gamut colorimeter not designed to work with modern backlighting units like W-LED, there can be a typical deviance of 300 - 600k in the white point measurement which is why some sources may refer to a different white point in this test incorrectly.

 

Luminance was recorded at a high, but not too bright 225 cd/m² which is a little too high for prolonged general use. The screen was set at a default 75% brightness in the OSD menu but that is easy to change of course to reach a more comfortable setting. The black depth was a very good 0.25 cd/m², giving us a very good contrast ratio of 910:1. This was very good for an IPS panel and a similar performance to what we had seen from the 24" U2412M in fact. Colour accuracy was pretty good at default factory settings with an average DeltaE (dE) of 2.6, ranging up to a maximum of 5.7. Along with the pretty good gamma and white point, this setup was pretty good really, even in this standard preset mode which doesn't carry any specific factory calibration.

 

 

 

 

Dell U2713HM - Default Settings, Custom Color Mode

   

 

We also tested the default performance in the 'custom color' preset. This mode allows you access to the individual RGB channels which will give you more control over the hardware when it comes to calibration. The performance in this mode was very similar overall to the 'standard' preset. The gamma remained at a similar 3% deviance but white point was now a little warmer than the target, being 3% out but measured at 6294k. You could spot this change in the colour temperature when switching between the two modes. Contrast ratio was actually a little higher at 962:1 which was excellent and colour accuracy remained pretty good at 2.6 dE average / 6.0 dE maximum.

 

 

Factory Calibration

Like its predecessor the Dell U2713HM comes factory calibrated to some extent, and the box even includes a calibration report from Dell specific to the unit you have. It states that every unit is shipped incorporating pre-tuned sRGB mode which offers an average DeltaE of <5. In addition to this, they have tweaked gamma and grey-scale to help to ensure smooth gradients and an accurate initial setup. Dell did not bother factory calibrating the 24" U2412M in this way or provide a calibration report, but it is nice to see it included on the U2713HM. I've included a copy of the calibration report from the Dell factory below for you to review. Note that this report is only relevant to our specific test unit and they do state that results may vary with each setup and different test equipment.

 

I was interested to see if this factory calibration helped at all with default settings. Note that this is only relevant for the sRGB preset mode available through the OSD menu. You will need to change from the default 'Standard' profile to benefit from these factory calibrated settings.

Dell U2713HM - Default Factory Calibration, sRGB mode

   

 

The factory calibration of the sRGB preset mode was very pleasing on the most part. This mode actually offered a reliable emulation of the sRGB colour space, helping to cut back the slight oversaturation of the screens native colour space and now very closely matching the sRGB reference. This might be useful for colour critical work in the sRGB colour space.

 

 

The average gamma remained 3% out from the target as we had seen in the standard and custom color modes out of the box. It was closer in dark grey shades but seemed to deviate quite a lot in the 50% grey measurements as shown in the table above. White point was actually now further away from the 6500k target, and was measured at 6007k. In fact the factory calibration report shown above which was included with the screen shows that the factory calibration was in fact aiming for 6000k grey-scale, and so we can't hold this against the screen for missing our normal 6500k target we use. In fact it was very well factory calibrated to Dell's target of 6000k. Luminance was still too high and this was perhaps the main area which deviated from our target. A simple OSD brightness change can of course overcome this though so this is no big issue. Contrast ratio remained strong at 925:1 and the colour accuracy was improved somewhat, now with a dE average of 1.8 and maximum of 4.2. A good overall factory calibration really, offering a close match to the targets Dell have used.

 

 

Testing Colour Temperatures

 

 

The U2713HM features a range of colour temperature presets within the OSD 'color settings' menu as shown above. You have to choose the specific 'color temp' preset mode first but you are then asked to define your target colour temp from the 6 presets available. We measured the screen with the X-rite i1 Pro spectrophotometer in each of the preset modes to establish their colour temperature / white point. All other settings were left at factory defaults and no ICC profile was active. The results are recorded below:

 

 

 

The colour temperature modes offered reasonable levels of accuracy overall with a maximum deviance from the target of only 4.4%. The coolest settings of 10,000 and 9300 seemed to be the furthest out from the target as a measurement with 377 - 409k difference from the desired settings (4.1% deviance). The 7500k mode was pretty close to the target but unfortunately it was the 6500k mode (which is probably the most commonly used white point for a general user) showed the highest deviance percentage and was measured at 289k too cool. The warmer settings of 5700 and 5000k were pretty close to their targets which was good. Overall the preset colour temp modes were reasonable.

 

 

Calibration Results

 

I wanted to calibrate and profile the screen to determine what was possible with optimum settings and profiling. I used the X-rite i1 Pro spectrophotometer combined with the LaCie Blue Eye Pro software package to achieve these results and reports. An NEC branded and customised X-rite i1 Display 2 was used to validate the black depth and contrast ratios due to lower end limitations of the i1 Pro device.

Dell U2713HM - Calibrated Settings, Custom Color Mode

Monitor OSD Option	Calibrated Settings
Brightness	35
Contrast	75
RGB Channels	93, 100, 99
Preset Mode	Custom Color

	Calibrated Settings, Custom Color mode
luminance (cd/m2)	120
Black Point (cd/m2)	0.14
Contrast Ratio	869:1

 

I first of all reverted to the 'custom color' mode in the preset section of the OSD menu which would allow me access to the individual RGB channels. Adjustments were also made during the process to the brightness control, and to the RGB channels as shown in the table above. This allowed me to obtain an optimum hardware starting point and setup before software level changes would be made at the graphics card level which would help preserve tonal values. After this I let the software carry out the LUT adjustments and create an ICC profile. The screen does not feature a hardware LUT calibration option so other than the OSD alterations, the rest of the process is carried out at a graphics card level in profiling the screen.

 

 

Average gamma had been corrected to 2.2 with 0% deviance according to the initial test correcting the default 3% deviance we'd found in this preset. Checking the more detailed table shown above, the gamma was slightly too high in the darker grey tones, and slightly too low in the lighter tones. The 3% deviance in the white point from our target of 6500k had also been corrected here and the colour temperature was now pretty much spot on. Luminance had also been corrected thanks to the adjustment to the brightness control, now being measured at 120 cd/m² spot on. This also gave us a calibrated black depth of 0.14 cd/m², and a static contrast ratio of 869:1 which was very good for an IPS panel. Colour accuracy had also been corrected nicely, with dE average of 0.3 and maximum of 0.8. LaCie would consider colour fidelity to be excellent now.

 

Testing the screen with various colour gradients showed mostly very smooth transitions. There was some slight gradation in darker tones and some very slight banding introduced due to the adjustments to the graphics card LUT from the profilation of the screen. Nothing major at all though. It's worth also commenting on the screen coating in this section of the review. Unlike many other IPS panels, this screen does not feature the usual heavy and aggressive Anti-glare (AG) coating which can sometimes lead to grainy and dirty looking images. Instead it uses a light AG screen coating and as a result the colours look more clean and crisp, the image quality is sharp and whites in particular look more pure than they do on heavy AG coated screens. It isn't a full glossy solution which adds another level of clarity and changes the overall feel of the screen, but it is an improvement over the heavy AG coating of some other IPS screens, including the previous Dell IPS models. A positive change and hopefully something we will start to see more of with future IPS screens.

 

You can use our settings and try our calibrated ICC profile if you wish, which are available in our ICC profile database. Keep in mind that results will vary from one screen to another and from one computer / graphics card to another.

 

 

Dell U2713HM - Calibrated Settings, Standard Mode

Monitor OSD Option	Calibrated Settings
Brightness	41
Contrast	75
RGB Channels	n/a
Preset Mode	Standard

	Calibrated Settings, Standard mode
luminance (cd/m2)	120
Black Point (cd/m2)	0.15
Contrast Ratio	813:1

 

I also carried out the calibration in the monitors 'standard' preset mode. Here you do not have access to the RGB channels at all, and so the only hardware changes being made are to the brightness control. The other corrections would be carried out at a graphics card LUT level through the profiling process. The results were again very pleasing. Targets for gamma and white point had all been met nicely, correcting the 3 and 4% deviations we had seen out of the box in this mode. The luminance had been corrected to the desired level with the change in the brightness control, and although it was a little lower than in the 'custom color' mode, the static contrast ratio was still a very good 813:1 after calibration. Colour accuracy had been corrected from the dE 2.6 average we had seen out of the box, now down to 0.4 dE average. Again testing the screen with various colour gradients showed smooth transitions on the whole, with some slight gradation and some very slight banding in some shades due to the graphics card corrections made.

 

Dell U2713HM - Calibrated Settings, sRGB Mode

Monitor OSD Option	Calibrated Settings
Brightness	41
Contrast	75
RGB Channels	n/a
Preset Mode	sRGB

	Calibrated Settings, sRGB mode
luminance (cd/m2)	120
Black Point (cd/m2)	0.15
Contrast Ratio	802:1

 

I also carried out the same process in the sRGB preset mode. This was factory calibrated out of the box and had offered a pretty reliable setup, along with an accurate emulation of the slightly smaller sRGB colour space. The calibration helped correct the slight 3% deviance we'd seen by default in the gamma. We also "corrected" the white point from the factory setting of ~6000k (which is how it had deliberately been set up) to our target of ~6500k. Colour accuracy had also been corrected from the 1.8 dE average we'd seen out of the box to now be 0.7 dE average.

 

This mode offered reliable performance out of the box anyway as long as you were happy with the 6000k white point and were able to manually turn the brightness setting down. After calibration it was also very reliable and corrected the slight offset we had seen in some areas, while also allowing us to reach a different white point if required. The emulation of the smaller colour space was also retained which was great news if you need to closely match the sRGB reference and avoid any slight oversaturation from the native gamut of the backlighting.

 

 

 

Calibration Performance Comparisons

 

 

I've provided a comparison above of the U2713HM against some of the other screens we have tested. Out of the box average dE was 2.6 which was pretty decent really and combined with the pretty good default gamma and white point represented a good initial setup. We have taken these results from the default 'standard' preset mode as well, while the sRGB mode carries an additional factory calibration which helps in some areas. It offered a similar level of accuracy to the HP ZR2740w (2.2) and also the DGM IPS-2701WPH (2.4) which are other 27" IPS + W-LED models. It also offered better default colour accuracy than the Dell U2711 (3.7 dE average) which had also shown a poor default gamma and white point setup. The professional grade 27" NEC PA271W and SpectraView Reference 271 were better thought as you might expect at 1.1 dE and 1.5 dE average respectively.

 

 

Once calibrated the dE average was reduced to 0.3. This would be classified as excellent colour fidelity by LaCie. It was not quite as low as some of the other screens here which reached down to 0.2 average, but in practice you would not notice any difference here at all. Some of the professional range models from NEC and Eizo for instance are even more accurate. Professional grade monitors like the NEC PA series and P241W also offer other high end features which separate them from some of these other models, including extended internal processing, 3D LUT's and hardware calibration. These comparisons are based on a small selection of tests, so it should be remembered that other factors do come into play when you start talking about professional use. For further information and tests of a high end professional grade screen with hardware LUT calibration, you may want to have a read of our NEC SpectraView Reference 271 review.

 

 

 

The calibrated black depth and contrast ratio of the U2713HM were very good for an IPS panel. With a static contrast ratio of 869:1 the U2713HM was only a little behind the 24" U2412M (947:1), but considerably ahead of the older 27" U2711 (672:1) which was positive news. The calibrated static contrast ratio was not as good as modern VA based screens however which can reach up to around 2000 - 3000:1. Nevertheless it was a good performance from an IPS panel and an improvement over the older U2711.

 

 

 

Contrast Stability and Brightness

 

The luminance range of the screen was very wide indeed. At a maximum brightness setting the screen reached 319.2 cd/m² which was a little shy of the specified 350 cd/m² maximum. This could be adjusted all the way down to a very low 19.5 cd/m² through changes to the brightness control, giving you a massive 299.7 cd/m² adjustment range. This should allow you a good control of the screens luminance for low ambient lighting conditions which is great news. A setting of around 35 - 40% should return you a comfortable luminance of ~120 cd/m². Black depth ranged from 0.36 at maximum brightness and went lower than 0.02 cd/m², which is the lower measurement limit of the X-rite i1 Display 2, when setting the brightness to 0%.

We have plotted the luminance trend on the graph above. The screen behaves as it should, with a reduction in the backlight intensity controlled by the reduction in the OSD brightness setting. This isn't quite a linear relationship though as the top 30% of the adjustment range seems to make steeper changes to the luminance than the bottom 70% of the range.

Static contrast ratio was excellent for an IPS panel, with an average of 907:1. This was stable across the range overall.

 

Dynamic Contrast

We tested the DCR feature and you could immediately notice the screen getting much brighter when you first turn it on compared with the standard preset. You can observe the changes being made in the OSD by looking at the energy meter in the top right hand corner. Switching to this mode in normal office-type applications showed the energy bar fill up to maximum, indicating that the brightness was being turned up to a high setting. When switching between an almost all-white and an almost all-black screen you could see the DCR change the luminance of the screen, both to the naked eye and by looking at the energy meter. However, it didn't seem to control a big range at all, only a few bars on the energy meter. The change was smooth but took only around 1.5 seconds to change between the two states. On an almost all-white screen we measured a maximum luminance of 249.4 cd/m², which wasn't quite as high as the max brightness we'd measured in the previous section of this review. The minimum black point measured was 0.21 cd/m² and this only resulted in a usable DCR of 1188:1. This wasn't much higher than our default static contrast ratio (907:1 average) but the DCR worked slightly.

We tested the screen with a completely black screen as well and you could tell from the OSD energy meter that it was then able to control the backlight all the way down to its minimum setting by the look of things. However, it should be noted that it would be extremely rare to ever see a 100% black image in real use and so this is more of a theoretical DCR than a realistic, practical DCR. If we assume that the screen could control the black point down to 0.01 cd/m² for arguments sake at the lowest brightness setting this would give us a DCR of ~25,000:1. This is still a long way off the quoted 2 million:1 spec of course, but that is very usual for modern displays boasting crazy DCR figures. In fact you'd have to be turning the backlight completely off on an all-black image to achieve anything higher really here. Some screens do actually do that which allows for crazy laboratory testing and their resulting specs, but in the case of the U2713HM it was not turning the backlight off.

We would like to start seeing realistic DCR figures being quoted from manufacturer really, not made up numbers which don't translate into real performance. I'd rather see a screen with a useable DCR of ~10,000:1 for example than a screen with an advertised 2 million:1 which only works in the most extreme and unrealistic circumstances that a user will never see. In the case of the U2713HM the DCR works slightly up to ~1188:1 but that's not really of much benefit in practice.

 

Viewing Angles

Above: Viewing angles shown from front and side, and  from above and below. Click for larger image

Viewing angles of the U2713HM were very good as you would expect from an IPS based panel. Horizontally there was very little colour tone shift until wide angles past about 45�. Contrast shifts were slightly more noticeable in the vertical field but overall they were very good. The screen offered the wide viewing angles of IPS technology and was free from the very restrictive fields of view of TN Film panels, especially in the vertical plane. It was also free of the off-centre contrast shift you see from VA panels and a lot of the quite obvious gamma and colour tone shift you see from some of the modern AMVA and PVA offerings. All as expected really from a modern IPS panel.

Above: View of an all black screen from the side. Click for larger version

On a black image there is a characteristics IPS white glow, but in normal working conditions this shouldn't present too much of a problem. The above image was taken in a darkened room to demonstrate the white wide angle glow when viewing a black screen. There is no A-TW polarizer on this panel which is rarely used now in the market but was implemented on some older screens to improve the off centre black viewing. If you are viewing dark content from a close position to the screen you can sometimes see this pale glow on parts of the screen towards the sides and corners because of your proximity to the screen and your line of sight. This is accentuated a little due to the sheer size of the 27" panel. The edges of the screen are at an angle from your line of sight which means you pick up this white glow to a smaller degree. This disappears as you move backwards away from the screen where the line of sight does not result in a wide angle view of parts of the screen and you can see the screen largely from head on. That is a little difficult to explain but hopefully makes sense. It is only really apparent on darker content and only really if you are working in darkened lighting conditions on this model. It was not too severe I didn't think, but something to be aware of.

Panel Uniformity

Measurements of the screens luminance were taken at 35 points across the panel on a pure white background. The measurements were taken using BasICColor's calibration software package, combined with the NEC customised X-rite i1 Display 2 colorimeter. The above uniformity diagram shows the difference, as a percentage, between the luminance recorded at each point on the screen, as compared with the reference point of a calibrated 120 cd/m². This is the desired level of luminance for an LCD screen in normal lighting conditions, and  the below shows the variance in the luminance across the screen compared with this point. It is worth noting that panel uniformity can vary from one screen to another, and can depend on manufacturing lines, screen transport and other local factors. This is only a guide of the uniformity of the sample screen we have for review.

Uniformity of Luminance

The luminance uniformity of the U2713HM was very good overall. There was some slight variance in luminance across the screen with the bottom half being a little brighter than the top half it seemed. Luminance ranged up to a maximum of 123 cd/m² (2.5% deviance) in the lower left hand region, but down as low as 105 cd/m² in the top left area (~15% deviance). Overall about 95% of the screen was within 10% deviance of the target and around 70% was within a 5% deviance. Not a bad result really on the whole.

Backlight Leakage

Above: All black screen in a darkened room. Click for larger version

As usual we also tested the screen with an all black image and in a darkened room. A camera was used to capture the result. To the naked eye, there did not appear to be much in the way of backlight leakage although you could notice the characteristic IPS-glow as you looked at the black image from different angles. The camera picked out some slight unevenness and some clouding from the backlight in the four corners. This was most apparent in the bottom right hand corner but in practice overall there was nothing too severe. There was no bleeding from the edges which was good to see as that can become quite distracting during some uses, for instance when watching a movie with black borders top and bottom.

General and Office Applications

The U2713HM features a massive 2560 x 1440 WQHD resolution which is only just a little bit less vertically than a 30" screen. The pixel pitch of 0.233mm is very small as a result, and by comparison a standard 16:10 format 24" model has a pixel pitch of 0.270mm and a 30" model has 0.250mm. These ultra-high res 27" models offer the tightest pixel pitch and therefore the smallest text as well. I don't find it too small personally, but day to day I am used to a 24" screen. Some users may find the small text a little too small to read comfortably, and I'd advise caution if you are coming from a 19" or 22" screen for instance where the pixel pitch and text are much larger. I found a 30" screen to be quite a change with text size when I first used one, and this is very similar and even a little bit smaller!

The massive resolution is really good for office and general use, giving you a really big screen area to work with. It is a noticeable upgrade from a 24" 1920 x 1200 resolution, and it's good to see Dell have stuck with the high res panel here rather than reverting to a 1920 x 1200 or 1920 x 1080 res panel as you may find in other older 27" models. For those wanting a high resolution for CAD, design, photo work etc, this is a really good option. The image was very sharp and crisp and text was very clear. The light AG screen coating ensured that the white backgrounds of office documents looked good, and did not suffer from the overly grainy and dirty feel of some IPS panels featuring heavy, aggressive AG coating. It also remained free from the reflections you might experience from a full glossy solution so seemed to be a good half-way between the two.

There was a defined 'text' preset mode which seemed to appear quite similar to the other standard mode, but could allow you to set up a comfortable setting for prolonged office use if you wanted to. Out of the box, the 75% default brightness is a little too bright for office use and measured at around 225 cd/m² in our tests. A setting of around 35 - 40% should return you a luminance close to 120 cd/m² for office use if you want, and you are able to control the brightness all the way down to around 19.5 cd/m² at the 0% setting which is excellent. Those wanting to use the screen in low lighting conditions shouldn't have any issue here. Another thing to note while we are talking about the brightness control is that the screen does not use Pulse-Width modulation (PWM) to control backlight dimming and so those who suffer from eye fatigue or headaches, associated with flickering backlights, need not worry here.

The stand provided offers a great range of adjustments which are smooth and easy to use. It's good to see a decent range of tilt, height, pivot and rotate adjustments available which should allow you to obtain a comfortable position for your office. If you want to, you can wall or arm mount the screen as well using the VESA 100mm option. With DisplayPort and DL-DVI both supporting the full 2560 x 1440 resolution you should have a decent choice for your PC connectivity. Since the VGA input was not able to support the full resolution of the screen we did not compare the sharpness of the image between analogue and digital, but the digital picture quality was excellent. There were 4x USB 3.0 ports included on this screen, with 2 available on the left hand side for easy access. It was good to see the upgrade to USB version 3.0 here for the faster transfer rates, and handy to have the easy access ports on the side for connection of printers, scanners, cameras etc. Dell have done away with the 8-in-1 card reader which was featured on the U2711 model unfortunately, something which I've always personally found quite useful. There are no integrated speakers on this model, but you can connect the Dell soundbar if you really want to (sold separately).

 
Above: photo of text at 2560 x 1440 (top) and 1920 x 1080 (bottom)

The screen is designed to run at its native resolution of 2560 x 1440 and at 60Hz refresh rate. If you want to you can run it outside of this and let the image be scaled to fill the screen. At the native resolution text was very sharp and clear. We ran the screen at 1920 x 1080 which was the next step down, while still maintaining the screens 16:9 aspect ratio. Text was actually very good and was hardly blurred at all. The screen is perfectly capable of being run at a lower 1920 x 1080 resolution if you wanted to, without much degradation in the picture quality and sharpness. To give you more desktop real estate and maximum picture quality, the native resolution is of course recommended where possible.

Update 7/11/12 - We have received a few user reports that the U2713HM exhibits a noticeable buzzing noise when viewing certain content. We have been able to re-create the issue on our sample as well, and it seems to be introduced when viewing full screen content with a lot of text. We've heard the buzz when viewing some spreadsheets full screen, but only when there is a lot of text within those sheets. It's hard to identify the exact cause, but is very rare to experience in practice. Indeed we have used the screen for many hours without problem, but occasionally the buzzing noise manifests itself if the conditions are right. Monitor OSD settings do not make any difference and it doesn't seem to be related to interface connection or anything like that. Not a major issue at all, but worth mentioning for completeness.

 

 

Responsiveness and Gaming

The U2713HM is rated by Dell as having a rather modest-on-paper 8ms G2G response time which implies the use of overdrive / response time compensation (RTC) technology, used to boost pixel transitions across grey to grey changes. The panel being used is an LG.Display LM270WQ1-SLB2 AH-IPS panel. Unlike some of the other Dell screens we have tested, including the U2412M, there is no control over this overdrive impulse from within the OSD or factory menu, and so you will have to rely on the setup by the manufacturer here.

The screen was tested using the moving car test in PixPerAn for the display comparisons. As a reminder, a series of pictures are taken on the highest shutter speed and compared, with the best case example shown on the left, and worst case example on the right. This should only be used as a rough guide to comparative responsiveness but is handy for a direct comparison of the impact of this setting:

 

27" 8ms G2G LG.Display AH-IPS

27" 6ms G2G LG.Display H-IPS

27" 6ms G2G LG.Display H-IPS

27" 6ms G2G LG.Display H-IPS

27" 12ms G2G LG.Display H-IPS

30" 7ms G2G LG.Display H-IPS

We have provided a comparison of the U2713HM first of all against four other popular 27" IPS models including the older Dell U2711 and the 30" Dell U3011. The U2713HM performed very well in these tests and seemed to have a decent manufacturer setup of the overdrive impulse. The moving car showed smooth movement with no obvious ghosting and only low levels of motion blur. There was some slight overshoot behind the moving car in the form of a small dark trail which you can pick out from the photos above and with a keen eye in practice. The older Dell U2711 had shown similar low levels of blur but had exhibited a far more obvious dark overshoot which is evident from the test photos above. Thankfully it seems Dell have improved their control of the overdrive impulse, or perhaps toned it down a little, and achieved a better result in practice when it comes to moving images. The U2713HM also performed a little better than the other four IPS models shown here which while all being free from any noticeable overshoot artefacts, did show a slightly higher level of blur to the image. A good performance from the U2713HM here.

 

27" 8ms G2G LG.Display AH-IPS

27" 5ms G2G Samsung PLS (Response Time = Faster)

27" 5ms G2G Samsung PLS (response time = faster)

27" 6ms G2G AU Optronics AMVA (SmartResponse = Fastest)

27" 8ms G2G AU Optronics AMVA (AMA setting = Premium)

27" 4ms G2G AU Optronics AMVA (AMA = Premium)

If you then compare the U2713HM with 5 other 27" screens we have tested which use AMVA or PLS panel technology there are more pronounced differences in some cases. The new Samsung S27B970D and older Samsung S27A850D had impressed us in these tests with its PLS panel technology and with a fast response time and very low levels of motion blur. They did not exhibit any noticeable overshoot from these tests but had a slightly more pronounced blur than the Dell. It was very close really in practice and they could be considered on par in terms of pixel responsiveness.

The Philips 273E3QHSB and BenQ EW2730V are based on AMVA panel technology and fell behind in these tests. The generation of AMVA panel being used in those two models was not able to compete with the responsiveness of modern IPS or PLS displays and there were high levels of blur evident, even with their response time controls turned up to the optimum levels. Those screens are rated with a 6ms and 8ms G2G response time respectively which just goes to show you can't always trust a specification when determining real life performance of a display. The recently tested BenQ GW2750HM had offered some improvements and showed lower levels of blur. However, it was again not as fast as the U2713HM in practice though.

 

27" 8ms G2G LG.Display AH-IPS

24" 6ms G2G LG.Display e-IPS (Video OverDrive = On)

24" 8ms G2G LG.Display e-IPS

23" 8ms G2G LG.Display e-IPS (W-LED)

24" 4ms G2G AU Optronics AMVA (AMA = Premium)

Above is a comparison of the U2713HM against some popular models in smaller sizes. First are three models using IPS panels, but in smaller sizes of 24" and 23". The HP ZR2440w had performed very well in these tests and showed a very similar performance to the U2713HM in fact, with low levels of blur and some slight overshoot. The overshoot was perhaps ever so slightly more noticeable on the HP and there was a very slight dark and pale halo trail evident in those tests. The 24" Dell U2412M and 23" U2312HM again offered low levels of motion blur but a more obvious dark overshoot trail was introduced which was certainly more pronounced than on this new U2713HM model. Dell have done a good job with the overdrive circuitry on this new model which is pleasing.

I have also included the results from our recent review of the 24" BenQ GW2450HM since there had been some big improvements made in AMVA panel technology in this most recent generation of panel. Thankfully the responsiveness was much better than we'd seen from the Philips 273E3QHSB and BenQ EW2730V we showed you above and was on par in practice with these IPS screens.

27" 8ms G2G LG.Display AH-IPS

24" 2ms G2G AU Optronics TN Film + 120Hz (AMA = On)

27" 1ms G2G Chi Mei Innolux TN Film + 120Hz (Over Drive = 0)

22" 3ms G2G Samsung TN Film + 120Hz

I've also included a comparison above against three very fast 120Hz compatible screens we have tested. In all cases these other screens are using TN Film panels and are aimed primarily at gamers. Firstly there is a direct comparison against BenQ's XL2420T. This showed very low levels of motion blur, but some dark overshoot was introduced as a side-effect. The recently tested Iiyama G2773HS was very responsive and even has a quoted 1ms G2G response time. This showed very low levels of blur and had minimal issue with overshoot. The Samsung SM2233RZ performed very well in these tests and showed very low levels of motion blur. When 120Hz mode was enabled the overdrive artefacts evident in 60Hz mode were almost completely eliminated, which is something we have seen here with the BenQ XL2420T as well.

There is something else going on here though as well which can't be picked out by the camera. All of these TN Film models are running at 120Hz refresh rates, which allows for improved 120fps frame rates and the support of 3D stereoscopic content as well. This can really help improve smoothness and the overall gaming experience so these screens still have the edge when it comes to fast gaming. From a pixel response point of view the U2713HM performed very well, but there are some other areas you still need to think about when it comes to high end gaming. It couldn't keep up with the very fast TN Film models with 120Hz support.

The responsiveness of the U2713HM was very good and we were pleased by what we saw. The screen showed very low levels of motion blur and only some very slight overshoot from the overdrive impulse being applied. It was a little ahead of the other 27" IPS panels we have tested and showed obvious advantages over some of the AMVA offerings in this size. Dell had made some improvements to the overdrive control as well since the U2312HM, U2412M and U2711 models and that was positive news. The screen should be perfectly capable of handling fast paced games, although you may want to consider the type of graphics card required to run games with high settings at such a high resolution.

Additional Gaming Features

Aspect Ratio Control - The screen offers three options within the OSD menu for hardware level aspect ratio control. There are options to maintain the aspect ratio at 16:9, 4:3 or 5:4 ratios which should be adequate for most users and for the connection of most external devices. It would have perhaps been useful to see an "auto" mode, capable of detecting and maintaining the source aspect ratio automatically, and perhaps a 1:1 pixel mapping mode for those who didn't want the source image stretched at all. Each of the modes provided would stretch the source image to fill as much of the screen as possible, but will maintain the selected aspect ratio. In addition even if the input source is not one of the specific aspects listed, it will be forced to that aspect if you select it. For instance if you input the native 2560 x 1440 resolution, but select 4:3 aspect, it will squash the screen sideways to meet a 4:3 aspect, but the image will just be squashed accordingly. It can be a little annoying having to manually change the aspect ratio each time if you input different aspect sources.

Preset Modes - There is a 'game' preset mode available from within the preset mode menu. This seems to be a little warmer than the standard preset mode and also gives you access to the dynamic contrast ratio if you want to use it. We've already established that the DCR doesn't offer much in real use but it's there if you want it. This mode might be useful if you want to set up a specific mode to be different to your day to day normal use profile as well.

 

Input Lag

We have recently written an in depth article about input lag and the various measurement techniques which are used to evaluate this aspect of a display. We have also improved our method by adopting the SMTT 2 (now version 2.5.1) tool which is used to generate the results below. Please see our full input lag testing article for all the details.

Input Lag Classification

To help in this section we will also introduce a broader classification system for these results to help categorise each screen as one of the following levels:

• Class 1) Less than 16ms / 1 frame lag - should be fine for gamers, even at high levels

• Class 2) A lag of 16 - 32ms / One to two frames - moderate lag but should be fine for many gamers. Caution advised for serious gaming and FPS

• Class 3) A lag of more than 32ms / more than 2 frames - Some noticeable lag in daily usage, not suitable for high end gaming

For the full reviews of the models compared here and the dates they were written (and when screens were approximately released to the market), please see our full reviews index.

Our tests here are based on the new format using SMTT 2. We have provided a comparison above against other models we have tested to give an indication between screens. However, please note that some of the other screens tested here were using older stopwatch methods and not the SMTT 2 tool. For reference, those shown as darker blue lines were tested using SMTT 2.

The Dell U2713HM showed an average total display lag of 22.2ms during this test, ranging up to 28ms maximum. Remember, this represents a signal processing lag along with an element of pixel response time and gives you an idea of the overall delay of the image compared with a traditional CRT screen. This lag was not too severe, but a bit higher than we had seen from some other recent screens, and represented a lag of just under 1.5 frames. The lag of this screen has been categorised as CLASS 2 as detailed above and may be a little high for some very high end gaming. Please note that we have included the Dell U2711 for reference here but that at the time it was measured using the less reliable single stopwatch method. A direct comparison between the two is therefore difficult. A comparison against other screens shown here which were tested using SMTT 2 (dark blue lines) is more accurate however.

We tested the screen in different preset modes including the 'game' option in case there was any bypassing of any internal electronics going on to help improve input lag. Unfortunately there was not and the overall lag remained the same in each mode.

 

Movies and Video

 The following summarises the screens performance in video applications:

• 27" screen size makes it a pretty good option for an all-in-one multimedia screen and comparable to smaller LCD TV's in size. A screen this big really does help lend itself to video viewing.

• 16:9 aspect ratio is more suited to videos than a 16:10 format screen, as it leaves smaller borders on DVD's and wide screen content.

• Native 2560 x 1440 resolution can easily support true 1080 HD content (1920 x 1080 resolution)

• Digital DL-DVI, DisplayPort and HDMI interfaces support HDCP for any encrypted and protected content

• Good to see DisplayPort and HDMI provided for connection of additional devices, both of which are very popular for external DVD and Blu-ray players.

• Light AG coating helps to ensure image quality is retained and not overly grainy, while also offering anti reflective properties which are useful for movie viewing, especially with lamps etc coming in to play in darkened room conditions. This is more suited to movie viewing than a full glossy coating.

• Contrast ratio was very good for an IPS panel, detail in darker scenes and shadow detail should not be lost as a result

• Dynamic contrast ratio is available but doesn't really do much in practice only offering a DCR of ~1188:1. You have to have a 100% black screen for it to function at a higher level which is probably never going to happen in real use.

• There is a 'movie' preset mode available in the OSD preset mode menu if you want to set up a mode specifically for your movie viewing. DCR is available in this mode as well

• Very good pixel responsiveness for movies and video which should be able to handle fast moving scenes without issue.

• Wide viewing angles thanks to IPS panel technology meaning several people could view the screen at once comfortable and from a whole host of different angles. The IPS glow from an angle might present a problem on darker content depending on your line or sight and distance from the screen

• Very good ergonomic adjustments available from the stand with full range of tilt, height and pivot being useful for obtaining a comfortable viewing position.

• No obvious backlight leakage from the edges which is good. This type of leakage may prove an issue when watching movies where black borders are present but it is not a problem here. Some slight clouding in the corners which might become evident in darkened room conditions sometimes.

• There are no integrated speakers available on this model although it is compatible with the Dell soundbar if you want. There is also a headphone socket provided on the back to take the audio from the HDMI or DisplayPort inputs if necessary.

• No picture in picture (PiP) or picture by picture (PbP) modes available on this model.

 

 

 

 

Dell U2711 Comparison

 

I know many people are going to be asking the question: "which is better, the old U2711 or the new U2713HM?" I'd like to start by saying that it is expected that the U2713HM will not be a direct replacement for the U2711 and much like the 24" models it will probably be a supplementary model in the UltraSharp range, aimed more at the mass consumer market and multimedia user. Like the 24" U2410, the 27" U2711 is aimed more at professional graphics users and higher end work while also offering an all round feature and function set. It is possible that things will change but we are not sure at this stage.

 

If I were to answer the question, I'd probably have to respond with "in many cases the U2713HM is better, but the U2711 has a few features and benefits which aren't available on the new model". As a start here is a summary of the main differences between the models. I won't compare the various specs as they are not really relevant in practice and I'll look instead at the performance comparison based on our tests:

 

 

Dell U2711 vs. U2713HM Comparison

 

 

Colour Space

 

Like the change with the 24" U2410 > U2412M, probably the main difference between these two 27" models is the colour space support. The U2711 uses wide gamut CCFL backlighting which offers an extended gamut covering 102% of the NTSC colour space. This can also cover the Adobe RGB reference space as a result and extends considerably beyond the sRGB reference which is still widely used. The support of wide gamut is great if you have a practical use for it and are working with wide gamut content or want to match the Adobe RGB space properly. However, if you are working just with sRGB content, viewing it on a wide gamut screen can lead to issues of over-saturation and neon appearing colours and is difficult to manage for many users. Thankfully the U2711 does include an sRGB emulation mode which is useful in those circumstances although not particularly accurate.

 

The U2713HM on the other hand uses modern white-LED backlighting which can only cover the sRGB reference colour space, offering >99% coverage according to the spec. It would be referred to as a standard gamut screen. This is therefore easy and practical if you are just working with standard gamut content, but obviously of no use if you need to work in a wider colour space as it cannot support it at all. The added sRGB emulation mode is a nice extra as it very closely matches the sRGB reference space, cutting back on any slight over-coverage from the native gamut.

 

The U2711 is perhaps more useful to colour enthusiasts, photographers and designers thanks to its wide gamut support, but for the general consumer, most will not need to use wide gamut and will only be concerned with the appearance of standard gamut (sRGB) content. As such they would not want the over-saturated colours and issues associated with trying to manage standard gamut on a wide gamut screen, and so a W-LED based model like the U2713HM is more readily accessible to the average user.

 

Factory Calibration

 

Both models carry a factory calibration as well which is positive news. The U2711 came factory calibrated to try and ensure a decent gamma, white point and colour accuracy out of the box in both the Adobe RGB and sRGB emulation modes. The Adobe RGB mode seemed to be pretty reliable in terms of gamma and colour accuracy, but white point was a fair way out from the target. The sRGB factory calibration on the U2711 was less reliable showing larger colour deviations and again a poor white point setup. The factory calibration on the new U2713HM only applies to the sRGB mode since there is obviously no Adobe RGB mode on this model due to the smaller colour space support. This offered very good levels of accuracy and seemed a more reliable setup to that seen on the U2711.
 

Colour Depth

 

I'll also make reference to the fact that the U2711 features an 8-bit + A-FRC panel which can offer a colour palette of 1.07 billion colours if you have a relevant end to end 10-bit workflow (application, operating system, graphics card, interface etc). That is very rare and so to 99% of users this support of "10-bit" is largely irrelevant. It's 12-bit internal processing is designed to help improve gradients and signal processing as well. These kind of features are usually reserved for high end graphics screens such as the NEC PA series, but Dell included them here on the U711 as well. The U2713HM uses only a normal 8-bit IPS panel and has 8-bit signal processing. This is more than adequate for most users, especially given the aforementioned complexities with achieving a 10-bit workflow. If you do have such a workflow and want support of 10-bit content then the U2711 would be a more suitable choice. I suspect many people just won't need it.

 

Features and Specs

 

The U2713HM is missing a few of the extra features found on the U2711 like the 8-in-1 card reader, DisplayPort cable and the composite and component inputs. The U2713HM does offer the latest generation USB 3.0 ports though while the U2711 was only v2.0. The stand on the U2713HM also offers a rotate function which wasn't present on the old style stand. The move to a W-LED backlighting unit also brings about energy and environmental benefits compared with the older CCFL unit and helps offer a thinner screen profile. One final thing to note is that the new U2713HM uses a light AG coating and so does not suffer from the grainy, dirty appearance in some uses that the heavy AG coating of the U2711 had.

 

Performance

 

I've included a table summarising these screens side by side based on the testing we have carried out and on my opinions. The screens are colour marked as green (winner) or red (loser) in each category which should be self explanatory. Where I was not able to separate the two they are shown in grey. I will justify each result below:

 

• Approximate price - at the time of release the new U2713HM is ~�65 more expensive than the U2711. This is probably down to the fact it is new more than anything else.

• Features - I've marked them level here as while the U2711 does have a card reader and composite and component inputs, the U2713HM has USB 3.0 and a rotate function. I suppose really the value of these features depends on what you're looking for from your screen and what you need.

• Screen coating - The U2713HM has a light AG coating and so does not suffer from a dirty, grainy appearance that the heavy AG coating on the U2711 can bring.

• Interfaces - The U2711 wins here as it offers composite and component inputs and an additional DVI, all missing on the new U2713HM.

• sRGB colour support - Being W-LED based the U2713HM is a native standard gamut screen and so its use with sRGB content is simpler than the U2711. It also has a more reliable factory calibration in the sRGB mode which is important to users who might not have other means to calibrate their screens

• Extended gamut support - The U2711 has a wide colour gamut, the U2713HM does not

• Panel Uniformity - I have marked these two screens as level in this test. Not much different overall.

• Office and Windows - There's very little to separate them here although I've marked the U2713HM as more suitable thanks to its lighter AG coating and the fact that it doesn't use PWM to dim the backlight.

• Viewing angles - No real separation here

• Movies Overall - Again I've had to mark them level. The U2711 has more video connections which some users might need, but the U2713HM has a better black depth and contrast ratio.

• Responsiveness - The U2713HM holds the advantage here as it has less blur and only a slight overshoot. The U2711 suffered from more noticeable overshoot artefacts.

• Input lag - hard to accurately compare since the U2711 was only tested using the old stopwatch method. I've provided the figures for reference but keep in mind the U2713HM is far more accurate than the old U2711 measurement.

• Colour accuracy Default - Out of the box, the U2713HM had a better setup in terms of gamma, white point and colour accuracy. The sRGB emulation mode also offered a better factory calibration than it had on the U2711.

• Black depth - The U2713HM wins here with a lower calibrated black depth of 0.14, compared with 0.18 of the U2711. A nice improvement made with this newer model.

• Calibrated Static Contrast Ratio - with a static number of 869:1, the U2713HM is the best in this test. The U2711 only managed 672:1.

• Dynamic Contrast Ratio - Neither worked very well at all, although the 1188:1 offered by the U2713HM was higher than the 759:1 of the U2711.

 

Overall there are some distinct differences between the two models as there had been between the two 24" models. The U2713HM brings about some positive changes we felt, certainly from a performance point of view. The default setup was more reliable and users will be pleased by the good gamma, white point and colour setup out of the box. The sRGB emulation mode works very well and is well calibrated in the factory. We had seen less impressive results from the U2711 model really and you'd probably need to calibrate it personally with a calibrator to get more out of it. The improvement to the static contrast ratio and pixel responsiveness were also very pleasing and a positive improvement from the new model. In addition the screen coating change to a light AG solution is very positive and welcome, and the inclusion of USB 3.0 ports and a rotation function from the stand are nice extras. It's a shame they did away with the card reader I felt, but we can live without the composite and component inputs which aren't really used much nowadays anyway.

 

The U2711 still has its place though as if you need/want wide gamut or 10-bit support then it can be offered on that model, but not on the U2713HM. Likewise if you need any of the additional interfaces then they are available there. I did feel though that the wide gamut support was really the only major advantage the U2711 had over the newer model (again only if you actually need or want it), and the new U2713HM showed plenty of performance improvements to make it an excellent new addition to the UltraSharp range.

 

Conclusion

The Dell U2713HM made a positive improvement to the UltraSharp series we felt. The screen is basically a larger version of the popular 24" U2412M in appearance, adopting the new style design and a more functional stand at the same time. The range of adjustments was excellent as ever and very easy to operate. The screen does away with a couple of the less common video connections of its predecessor but does introduce the latest USB 3.0 standard for faster transfer rates. One of the most pleasing changes is the move to a lighter AG coating, which should keep those bothered by aggressive, grainy AG coating on IPS panels happy. From a performance point of view the screen offered excellent all round performance from its IPS panel. The default setup was very good, and the screen even offered a usable sRGB emulation mode and accompanying reliable factory calibration. Black depth and contrast ratio were very good for an IPS panel and showed some marked improvements over the older U2711. Pixel responsiveness was also very good and again helped clear up most of the overshoot issues which affected the U2711 before it. Brightness range and control was excellent and it was great to see that PWM was not being used for backlight dimming.

As we've discussed during the review, the U2713HM is missing any wide gamut and "10-bit" support but that's probably not an issue for many users anyway. We did feel the improvements made in other areas made the U2713HM a better screen as long as you don't need those aspects for your personal uses. The price point of the U2713HM is maybe a little higher than some people had hoped for, certainly at the time of writing and initial release. The U2713HM retails for ~�492 GBP (inc VAT) in the UK at the moment making it a little less than the older U2711 (�500).  Both are of course more expensive than some of the low-cost and no-frills 27" IPS models available now like the Hazro HZ27WC (�385) and DGM IPS-2701WPH (�335), but the added features and extras of the Dell do separate this as a higher end model. Keep in mind also the support and warranty from a company like Dell when making a decision.

All in all we were impressed by the new 27" screen from Dell. It made a lot of positive improvements and offered the kind of all round performance you'd want from any screen. Certainly a very good new addition to the Dell range.