Like the U2311H, the Dell U2312HM 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. The OSD menu itself is pretty much identical to the 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. and custom colour.

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 was also featured on the U2412M. 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 auto adjust section is only relevant when using the analogue D-sub connection.

The input source section allows you to manually select which interface is in use, unless you want to use the pretty useful 'auto select' option.

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.

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 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. As with the U2412M, perhaps of some interest here is the ability to turn the overdrive ("OD") function on and off. By default it is turned on, but we will test both settings later on in the review out of interest.

Overall the OSD menu offers a decent range of options and it is intuitive and well structured. No issues here.

Power Consumption

Dell's new PowerNap software comes on the CD that shipped with the monitor. This software provides a Power Saving mode for your monitor. The Power Saving mode lets users set the monitor to "Screen Dim" or "Sleep" when your PC enters the screen saver mode.

1. Screen Dim - the monitor dims to a minimum brightness level when the PC is in the screen saver mode.
2. Sleep - the monitor enters the sleep mode when the PC is in the screen saver mode.

In terms of power consumption the manufacturers spec states typical usage of 30W in normal operation and 70W maximum (with Dell Soundbar, maximum luminance and USB active). In standby the screen apparently uses <0.5W.

We tested this ourselves and found that out of the box the screen used 24.8W of power while at its default 75% brightness setting. After calibration, where we had adjusted the brightness control to 20% and therefore the backlight intensity, this was reduced to 19.3W. In standby the screen uses only 0.6W of power. This was quite comparable of course to the other W-LED models we have tested when you compare calibrated and standby power consumptions although in many cases it was a bit lower. I have plotted the results of these measurements on the graph below:

Colour Accuracy, Black Depth and Contrast

The Panel and Backlighting Unit

The Dell U2312HM utilises an LG.Display LM230WF3-SLD1 e-IPS panel which is capable of producing 16.7 million colours. The panel itself actually uses a 6-bit colour depth with Advanced frame rate control (A-FRC) to produce the 16.7m colours. This is different to regular 8-bit IPS matrices, but this is a measure taken to achieve a lower price point for these modern lower-cost displays. This has been confirmed by Dell.

The U2312HM uses White-LED (W-LED) backlighting. The colour space of this screen is approximately equal to the sRGB reference and is considered a 'standard gamut' backlight type. Studying the detailed panel spec confirms the screen covers 73% of the NTSC reference, 76.0% of the Adobe RGB reference and 96.9% of the sRGB space. As a side note you will see reference on Dell's website of an 82% colour gamut. This refers to the NTSC coverage but is based on a different reference point (CIE1976 = 82%). More common is the CIE1931 standard which would equate to 72% NTSC which is more relevant when comparing with other screens quoting NTSC gamut specs. While a 96.9% coverage of the sRGB space is decent enough and in line with most W-LED backlit screens, some higher end uses may require a wider gamut with a full 100% sRGB coverage (and beyond) for graphics and colour work. A wide gamut screen is another option for those wanting to work outside of the sRGB colour space.

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 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 in a 2D view, with the black triangle representing the displays gamut, and other reference colour spaces shown for comparison

• 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 settings of the screen were as follows:

Dell U2312HM - Default Factory Settings

The out of the box performance of the U2312HM was reasonable. The CIE diagram on the left confirms that the monitors colour gamut (black triangle) very closely matches the sRGB colour space (orange triangle). It extends a little past the sRGB space in greens in this 2D view of gamut but is a little short in reds.

Default gamma was recorded at 2.1 average, leaving it 5% out from the target of 2.2. Gamma was actually closer to the target 2.2 in the darkest and medium greys where it was recorded at 2.15 and 2.14. This deviated as low as 1.91 in other lighter shades however. White point was a little out here at 6140k which was 6% out from the target. We had seen a better default white point from the U2412M which was 6497k, so this was a little disappointing that the U2312HM was a little way out. 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 colorimeter with a W-LED backlit screen 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 215 cd/m² which is too high for comfortable use. The OSD is set at 75% brightness and this is still too much. At this high 215 cd/m² luminance, the black depth was a pretty good 0.25 cd/m². This gave us a static contrast ratio of 868:1 which is good for an IPS panel, although not as good as the U2412M (1106:1) or in fact the U2311H default contrast ratio when we tested that (995:1).

Colour accuracy was fairly good at default factory settings with an average DeltaE (dE) of 2.2, ranging up to a maximum of 4.9. The screen felt a little yellow-ish to the naked eye and overly bright at these default settings. Some minor OSD adjustments to the brightness can hopefully help improve the default set up for casual users who don't have access to a hardware calibration device. To be fair though this kind of out of the box set up should be fine for most casual users anyway, and they can just adjust the brightness control to suit their working environment.

Testing Colour Temperatures

Like the U2412M, the U2312HM features a preset which we have not seen on previous models, that being the 'Color Temp' mode. Once selected you are presented with a range of options ranging from 10,000k to 5000k, depending on how cool or warm you want your white point to be. We have already seen that the 'standard' preset mode which is selected out of the box returns a white point / colour temperature of 6140k, which is close but slightly out from the target in our tests of 6500k (6% deviance).

We measured the colour temperature of the screen with the X-rite i1 Pro spectrophotometer in each of the preset modes to establish how accurate the settings actually were. All other settings were left at factory defaults and no ICC profile was active. We disabled dynamic contrast ratio as well when testing modes where it became active. The results are recorded below:

As you can see, there is a minimal deviance between the supposed colour temp mode and that actually recorded at the cooler settings. There is only 100k difference at the highest 10,000k setting for instance. As the setting is made warmer, the deviance increased to 200 - 350k as shown in the table above. The 6500k mode, which is perhaps the most commonly used, is 362k different which is a shame as we would have hoped this would have been a bit closer to the 6500k target.

We also measured the colour temperature of each of the named preset modes as shown above. The 'movie' mode makes the image a bit cooler, while the other modes are all quite similar to one another at around 6100k.
 

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.

I first of all remained in the default 'standard' preset mode. This preset does not allow you to adjust the individual RGB channels so the only hardware adjustments I would be making potentially are to the brightness and contrast levels. I followed LaCie's calibration process through, adjusting the OSD brightness setting in line with the recommendations made in the process, and then letting the software carry out the LUT adjustments at a graphics card level 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.

The calibration was a great success. The gamma discrepancy that we saw before (6%) had been almost completely corrected now to leave us with 1% deviance and an average gamma of 2.2. White point was also corrected to 6530k, bringing it <0.5% out from the target. Luminance had been reduced to a more comfortable 121 cd/m² after the adjustment of the OSD brightness control to 20%. Black depth was still good at 0.16 cd/m² and this gave us a reasonable, but not very impressive, calibrated static contrast ratio of 770:1. Colour accuracy was also improved nicely with dE average now only 0.4 and maximum only 0.8. LaCie would consider colour fidelity to be excellent.

Testing the screen with various colour gradients showed fairly smooth transitions with some slight gradation in darker tones being evident. There was some slight banding in darker tones as well but this was very minimal and only really visible with gradients and not in normal use.

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. You may also instead want to use our 'custom color' mode as discussed in the next section.

Dell U2312HM - Calibrated Settings, Custom Color Mode

I switched to the 'Custom Color' preset  mode for this process as it would allow me to change the individual RGB channels. I followed LaCie's calibration process through, adjusting the OSD settings in line with the recommendations made in the process, and then letting the software carry out the LUT adjustments at a graphics card level and create an ICC profile. In this mode I was making further adjustments at the hardware level during the process by changing the RGB channels, which was not possible when profiling the 'standard' mode.

The calibration was again a success. The performance pretty much matched that of our calibrated 'standard' preset. With a reduction in the RGB levels you are also affecting the contrast ratio of the screen a little, and so calibrated static contrast ratio was 60 lower in this 'custom color' mode than it had been in the 'standard' mode, being recorded at 710:1. This mode might give you more flexibility via the RGB channels if you are trying to calibrate without the use of a colorimeter and it did appear that the slight banding we had seen in the 'standard' mode had been eliminated on the most part which was pleasing. This mode might be a better option for new users.

There was also some very slight temporal noise evident, particularly in darker tones if you look very closely. This is a result of the FRC algorithm used to produce the 16.7 million colour palette. It's not something you'd notice in practice, and you do have to look very closely to see it. In reality although the panel used is a 6-bit + A-FRC module, there is no noticeable issue with this in terms of colour gradation and performance.

Again, you can use our settings and try our calibrated ICC profile if you wish, which is 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.

 
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Calibration Performance Comparisons

I've provided a comparison above of the U2312HM against some of the other screens we have tested in a similar size range. Out of the box average dE was 2.2 on the U2312HM which was very good really. The default colour accuracy of the U2312HM was comparable to some of the other 23" IPS models we have tested including its predecessor the Dell U2311H (2.4), the NEC EA231WMi (2.7) and ViewSonic VP2365wb (2.5). Even though the U2312HM was a little lower at 2.2 this is a minimal difference really out of the box. Some of the other 23" IPS + W-LED screens we have tested are also quite similar such as the NEC EA232WMi (2.4), LG IPS231P (3.1) and the Asus ML239H (2.3). The slightly larger 24" Dell U2412M was not quite as good either at 3.2 average dE. The professional grade 23" NEC PA231W was better still at 1.3 dE average. A reasonable performance in terms of default colour accuracy from the U2312HM and only a little behind the competition really. Some form of software profiling using a colorimeter would of course be beneficial to correct some of the colours.

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. Some of the professional range models from NEC are even more accurate. Professional grade monitors like the NEC PA series 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 black depth and contrast ratio of the U2312HM were ok, but not great for an IPS panel. Calibrated black depth was 0.17 cd/m² which left it a little behind some of the other models we have tested and gave us a static contrast ratio of 710:1. I have used the black depth from the calibrated 'custom color' mode since that had returned the best performance in our tests. The black depth and CR were even a little behind the older CCFL based U2311H model (857:1) which had impressed us at the time in this area. The new U2412M was also very impressive more recently with a 947:1 calibrated CR.

The 710:1 contrast ratio figure was not bad per-say, but we had perhaps hoped for a bit more. It was quite similar to the Asus ML239H (749:1) though, but both these screens were behind some of the other W-LED + IPS panels like the NEC EA232WMi (933:1) and LG IPS231P (860:1).

The BenQ EW2420 and Samsung F2380 with their AMVA and cPVA panels respectively offered some fantastic contrast ratios of ~3000:1 which IPS cannot compete with at the moment.

Contrast Stability

The luminance range of the screen was quite wide with an adjustment range of 236.9 cd/m² possible. At maximum brightness the luminance was recorded at 351.1 cd/m² which was very high, and even 51 cd/m² above the specified maximum brightness of the panel. At the lower end however the luminance only ranged down to 114.2 cd/m² which could present a problem for those wanting to use the screen in low light conditions. Those wanting to use the screen at a luminance of ~ 120 cd/m² will of course be fine and a setting of around 5 -10% out of the box should return a comfortable luminance close to this. However some users do like a luminance much lower than this, especially where they are working in darker room conditions. Sadly this screen could not reach the very low luminance of the U2412M which was measured at 46 cd/m² at 0% brightness. The U2311H had also reached a little lower at 82 cd/m².

Black depth was reduced as one would hope as you lower the brightness control. This ranged from 0.41 cd/m² at the top end down to a reasonably low 0.14 cd/m² at the bottom end.

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. Between 70 and 100% the brightness range controlled is actually steeper it seems as the line is not linear.

Static contrast ratio remained pretty even across the adjustment range, with an average figure of 848:1 which was good. It was a little less stable at the lower end of the brightness range below a setting of ~40%. These contrast measurements were plotted on the graph shown above.

Dynamic Contrast

The tests that we carry out to measure dynamic contrast ratio involve an almost completely white and almost completely black screen. In real use you are very unlikely to ever see a full black or full white screen, and even our tests are an extreme case to be honest. Carrying out the tests in this way does give you a good indication of the screens dynamic contrast ratio in real life situations however.

Like the U2412M, carrying out this test didn't seem to make use of the DCR at all. There was no noticeable change in the backlight intensity when changing between images of different levels of white and black, even when switching between an almost completely white, and an almost completely black image. Watching the OSD menus energy bar also allowed you to see what was being changed and it remained static throughout. Our colorimeter recorded maximum luminance as 239 cd/m² and minimum black depth of 0.40 cd/m². This gave us a contrast ratio which was in fact much lower than the the default static contrast ratio and was recorded at 595:1. The DCR didn't seem to work at all. Nothing particularly surprising considering some of the DCR performances we have seen from many other models.

However, the feature can work, but only in the most unrealistic and extreme circumstances. Like the Dell U2412M, Asus ML239H and LG IPS231P that we tested recently, if you display an all black screen (completely black) then the feature "works". You can see a change when viewing an all black screen which takes about 2.5 seconds to happen. This was a quicker change than on the U2412M which had taken ~4.5 seconds to change.

If you bring up the OSD menu and switch to a completely black screen you can see the green energy meter lowering slowly from maximum, to minimum. Unlike the Asus and LG models however we did not see the backlight being turned completely off and so what you are basically doing is controlling the full range of the backlight intensity in the space of around 2.5 seconds. In real use you are never going to have a 100% black screen so this features use is very questionable. If it did operate under less extreme circumstances you could in theory get a maximum luminance of 351.1 cd/m² and a minimum black level of 0.14 cd/m². Those figures are taken from our contrast stability section and would in theory give you a dynamic contrast ratio of ~2508:1. That would be a fairly low figure but may be of use to some people at least. The screen would never live up to its 2 million:1 spec though as you would have to be turning the backlight off to reach a lower black point than 0.14 cd/m². In fact it would be then tending towards infinity:1 if you consider its black point is basically then 0 cd/m². However, in practice you are never going to be able to see a DCR range like that. In fact in normal use the DCR doesn't seem to operate at all. Another marketing gimmick and a disappointing trend we've seen.

Viewing Angles

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

Viewing angles of the Dell U2312HM are very good, as you would expect from a screen based on an e-IPS panel. Horizontally there are very wide fields of view with a small contrast shift only really becoming noticeable from a fairly wide angle of about 45�. At more extreme angles the image goes a little darker but in fact this was not as noticeable as on some other e-IPS panels we've tested including the Dell U2412M. Darker areas tend to become a little more washed out though which impacts the already mediocre contrast ratio. Vertically, the contrast shift was similar and the fields of view were still good. The panel is free from any off-centre contrast shift which you see from VA matrices, and this is why IPS technology is so highly regarded in the colour enthusiast and professional space. It is also free of the very noticeable contrast and colour tone shifts you see from TN Film panels vertically.

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 much problem. The above image was taken in a darkened room to demonstrate the white wide angle glow. 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 because of your proximity to the screen and your line of sight. 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.

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 U2312HM was very good. There was very minimal variation across the whole screen as compared with a central measurement of 120 cd/m². The luminance ranged from a maximum of 125 cd/m² (central left hand portion) down to 108 cd/m² (right hand edge). 86% of the screen was within only 5% deviance of the target and 97% was within 10% deviance. This was a positive result and showed a good performance. Results may of course vary from one screen to another but the sample we had was provided randomly from an actual retail stock so was a promising indication perhaps.

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. There was very little leakage from the backlight unit here which was pleasing. There was some slight variance from the four corners, with the most noticeable leakage coming from the bottom right hand corner. This was not too severe at all and not something you'd notice in practice. A good result again from this relatively low cost display.

General and Office Applications

The U2312HM has a nice high resolution of 1920 x 1080 which is good for side by side office work. I don't think it's as practical as a 16:10 format screen with 1920 x 1200 resolution though as you do lose a bit vertically and the screen did feel smaller than a 'normal' 24" model. The aspect ratio of this screen is a pretty common trend in today's market with the move to multimedia orientated displays and widescreen formats. With a pixel pitch of 0.265mm, the text was comfortable and of a decent size for prolonged office use. Picture quality was very good using the DVI and D-sub connections, with DVI providing a slightly sharper image.

You will want to turn down the default brightness setting for the screen as the luminance is too high out of the box. A reduction from 75% to around 5 - 10% should return a more comfortable luminance around the 120 cd/m² mark out of the box. The screen is not able to offer a lower luminance than about 114 cd/m² without other adjustments at a graphics card / contrast level, which will impact contrast ratio. This is perhaps an issue for those working in darker ambient lighting.

There is a preset mode available for 'text' but this made the image brighter and a little more yellow-ish than our calibrated 'custom color' mode. Some models are starting to use ambient light sensors and dynamic brightness control which I think can be useful for office use. It's not featured on this model however although the competing NEC EA2312WMi does have one.

Ergonomically the screen was very good, with a decent and smooth range of tilt and height adjustments available. There's a rotate function as well in case you want to work in portrait mode. The easy access 2x USB 2.0 ports on the left hand side are useful for connecting printers, cameras etc, but it might have been nice to have a card reader as well like on some of the other models like the 24" U2410.

 
Above: photo of text at 1920 x 1080 (top) and 1680 x 1050 (bottom)

The screen is designed to run at its native resolution of 1920 x 1080 and at a 60Hz recommended refresh rate. However, if you want you are able to run the screen outside of this resolution. We tested the screen at a lower 1680 x 1050 resolution to see how the screen handles the interpolation of the resolution. At native resolution the text was sharp as you can see from the top photograph. When you switch to a lower resolution the text is a little more blurry, but not quite as severe as some other screens we have tested. There is some minimal overlapping of the text across sub-pixels as you can see in the photo which results in this blurring. Native resolution is recommended where possible.

Responsiveness and Gaming

Response Time Control

Before we get in to the get into the side by side screen comparisons I want to quickly talk about the overdrive control available through the screens factory menu. Dell have not made this option available through the normal OSD menu, but if you want, you can turn it on and off. It is labelled in the factory menu under "OD" as shown above.

The screen was tested using the chase test in PixPerAn, a good bit of software for trying to quantify differences in real terms responsiveness between monitors. As a reminder, a series of pictures are taken on the highest shutter speed and compared. The images above are the best case examples from the U2312HM with the overdrive (OD) function disabled and then enabled. When OD is turned off there is a more pronounced motion blur which is noticeable to the naked eye. It doesn't have any severe ghosting but the blur is certainly more obvious. When you enable OD the blur is reduced but there is still some minimal motion blur detectable. While the blurring is improved quite nicely, the OD impulse does introduce a bit of an overshoot in the form of a dark trail behind the moving car. This is caused by the aggressive application of an overdrive impulse, causing the pixels to change orientation too far before reverting to the desired position. This characteristic trailing can happen on screens where overdrive impulses are applied, where it is either too aggressive (to try and boost response times even more) or poorly controlled.

Like the U2412M, in the case of the U2312HM this is not too bad and should not prove a major distraction during normal use. We will look at the screens performance in more detail in a moment, but from a pixel response time point of view it is beneficial to have the OD function turned on (as it is by default). This was a very similar story to the U2412M which performed almost identically in these tests.

Display Comparisons

The screen was tested again using the chase 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:

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

23" 5ms G2G LG.Display e-IPS (W-LED)

23" 14ms LG.Display e-IPS (W-LED)

23" 5ms G2G LG.Display e-IPS (W-LED) - Trace Free setting 40

The U2312HM is rated by Dell as having an 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. We know this to be true as we have already looked at the OD function available in the factory menu. The panel being used is an LG.Display LM230WF3-SLD1. Have a read about response time in our specs section if any of this is new to you.

I have provided a comparison of the U2312HM first of all above against 3 other screens we have tested which use IPS panel technology and W-LED backlighting. The U2312HM shows less motion blur in moving images than the LG IPS231P despite that screens rather bold spec of 5ms G2G. In fact we had already concluded from our review that the IPS231P performed much like the NEC EA232WMi which has a 14ms response time and does not use RTC technology. This goes to show that you can't always trust a reported spec. The U2312HM shows a similar low level of motion blur to the 5ms G2G rated Asus ML239H, but does have a more noticeable overshoot and dark trail unfortunately.

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

24" 8ms G2G LG.Display e-IPS (W-LED)

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

I have provided a comparison of the U2312HM against some other models in Dell's monitor range. The U2312HM performs very comparably to the new 24" U2412M overall. It has the slight edge in a side by side comparison as the blur felt a little less and although there was some overshoot evident, it was not quite as dark and pronounced as the U2412M. This was close, but the U2312HM did perform slightly better I felt.

It is quite similar to the older U2311H model although there is a darker overshoot artefact on the new model whereas the older U2311H showed a pale overshoot instead. In both cases this is very slight and so won't be a problem to most users at all. Since the pale overshoot is a little less noticeable than the dark overshoot, the U2311H has perhaps the slight edge in responsiveness as a result here I think.

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

24" 6ms G2G LG.Display H-IPS

21.5" 8ms G2G LG.Display e-IPS

27" 6ms G2G LG.Display H-IPS

The U2312HM shows some slight improvement compared with the U2410 in terms of motion blur but does introduce this dark overshoot artefact unfortunately as a result. The U2211H is a tad slower with a bit more motion blur, but no obvious overshoot. The U2711 shows a more aggressive and obvious overshoot of the RTC impulse and the dark trail behind the moving object is more pronounced which is unfortunate.

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

24" 8ms G2G AU Optronics AMVA (W-LED)

23" 8ms G2G Samsung cPVA (Response Time setting = Fastest)

24" 5ms G2G LG.Display e-IPS

I have also provided a comparison of the U2312HM against other competing 23" - 24" models here outside of Dell's own range. The U2312HM offers the least motion blur out of these 4 models shown, and certainly a marked improvement over the fairly slow cPVA based Samsung F2380, and frankly quite disappointing AMVA based BenQ EW2420. The IPS HP ZR24W is a reasonable performer with only minimal motion blur and no overshoot. It is not quite as responsive as the U2312HM which performs very well in this sector.

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

23.6" 2ms G2G CMO TN Film (120Hz)

22" 3ms G2G Samsung TN Film + 120Hz

I've also included a comparison above against two gamer-orientated screens, both featuring heavily overdriven TN Film panels, and 120Hz technology. The pixel responsiveness of both of these is ahead of the U2312HM, and the 120Hz frequency allows for improved 120fps frame rates and the support of 3D content as well. The BenQ XL2410T does show some even more obvious RTC overshoot in the form of very dark trails behind the moving image (speech bubble and head) which is unfortunate, and a sign that the RTC impulse is too aggressive. The Samsung 2233RZ remains our champion in this test.

The responsiveness of the U2312HM should be perfectly fine for most moderate to high gaming and shows a nice low level of motion blur assuming you leave the OD control turned on. The small overshoot is a shame really as the dark trail is an unwanted result of the applied RTC impulse. Having said that, it isn't as bad as some other models we have seen including Dell's own U2711 and certainly the gamer orientated BenQ XL2410T. There's not much in it when comparing the pixel responsiveness of the U2312HM and older U2311H but the older model perhaps has the slight edge I think as the overshoot is pale and slightly less obtrusive than the dark overshoot of the newer model. Still the new screen is a very good choice as a 23" IPS screen for gaming.

Additional Gaming Features

Aspect Ratio Control - The U2312HM supports aspect ratio control options through the OSD 'display settings' menu as shown above. There are options for wide 16:9, 4:3 and 5:4 aspect here. A defined 1:1 pixel mapping mode is lacking here.

Preset Modes - There is a 'game' preset mode available in the menu if you want it. We have tested the screen and found the colour temperature remains similar to the 'standard' mode at ~6100k. The dynamic contrast ratio is available in the game preset whereas is it not in the standard mode, although we have already seen that this does nothing in real use unfortunately.

Input Lag

As usual I tested the screen against a CRT to determine the level of input lag of the TFT. This is something which can put off some gamers and is a delay between graphics card and monitor output. By hooking up a CRT you can show that  the LCD lags behind somewhat, which can affect users in some situations where they rely on the screen image being as fast as their inputs (e.g. fast FPS shooting games). Often, input lag is very low and probably wouldn't represent too much of a problem in real terms.

The input lag of the U2312HM was incredibly low, and in fact the lowest we have ever seen from a TFT display. There was practically no delay at all with most measurements showing 0ms lag compared with the CRT. There was an occasional lag of up to 10ms but over many measurements we had an average lag of only 0.6ms. This was lower than the already very good U2311H (10.3ms) and the new Dell U2412M (9.4ms). Excellent work here from Dell to bring lag down to such a low level. This will present no problem, even to high end gamers.

Movies and Video

 The following summarises the screens performance in video applications:

• 23" screen size makes it a reasonable option for an all-in-one multimedia screen, although quite a bit smaller than modern LCD TV's of course

• 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.

• 1920 x 1080 resolution can support true 1080 HD resolution content

• Digital interface DVI supports HDCP for any encrypted and protected content

• Additional DisplayPort interface is available although it would have been useful to feature HDMI as well here as it is popular and very useful for external Blu-ray / DVD player connectivity.

• Black depth and contrast ratio are good for an IPS panel although not as good as some other models we have tested. Detail in darker scenes and shadow detail should not be lost due to these measurements.

• Dynamic contrast ratio is available but does nothing in practice unfortunately.

• 'Movie'' preset mode is available from the preset menu. This made the image a bit cooler than the standard mode and provided access to the DCR mode (which as we've said, does nothing).

• Good pixel responsiveness which should be able to handle fast moving scenes in movies without issue.

• Wide viewing angles thanks to e-IPS panel technology meaning several people could view the screen at once comfortable and from a whole host of different angles.

• Very good ergonomic adjustments available from the stand allowing you to obtain a comfortable position for movie viewing.

• No significant backlight leakage from the panel which was pleasing. Thankfully no leakage along any of the edges which has the potential to become distracting when watching movies, especially where black borders are present.

• No integrated stereo speakers on this model but it is compatible with Dell's sound bar for some light sounds for movies if needed.

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

Dell U2311H Comparison

I know many people are going to be asking the question: "which is better, the U2311H or U2312HM?" Unlike with the 24" model, the U2312HM is a direct replacement of the U2311H, being part of their almost annual refresh and moving the range away from CCFL backlighting and to W-LED instead. I will provide a comparison here between the new and old model to help you understand what has changed both from a technical and from a performance point of view.

Dell U2311H vs. U2312HM Comparison

Backlighting

The major change since the U2311H model has been Dell's move towards W-LED backlighting from CCFL. Both screens offer a standard gamut colour space, but W-LED is certainly the popular choice of manufacturers at the moment. This has environmental and energy saving implications which are of course attractive given the focus on carbon footprints and the like. The LED panels are arsenic and mercury-free for example. Unfortunately at the time of our U2311H review we did not measure the power consumption like we do in our current reviews. However as an indication FlatpanelsHD measured the U2311H as having a 25.2W power consumption after calibration (to 120 cd/m²) and we have measured the U2312HM as being slightly lower once calibrated at 19.3W (FlatpanelsHD measured 21.8W for completeness).

It should be noted that W-LED backlighting does not necessarily offer you any advantages in terms of colour reproduction, contrast ratios, black depth, or uniformity. These are often incorrectly assumed to be impacted by the change, when in fact those are features of the panel itself rather than the backlighting unit employed. The use of W-LED does allow for a thinner profile of the screen with the U2312HM measuring 59.5mm depth, while the U2311H was 65.0mm.

Features and Specs

The U2311H and U2312HM are pretty much identical here, and the only thing that has really changed is the design. The U2312HM has more rounded edges to the bezel and stand compared with the rather square appearance of the U2311H.

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 - perhaps not a fair comparison since the U2311H is pretty much withdrawn now. It is still available in some places and at the moment retails at a slightly higher price than the new U2312HM replacement

• Features - Both the same

• Interfaces - Both the same

• Calibrated power consumption - * This has been compared based on the measurements at FlatpanelsHD, but the calibrated consumption of the U2312HM is a little lower thanks to its W-LED backlighting.

• Panel Uniformity - The U2312HM wins here with a much better luminance uniformity than the U2311H from our tests

• Office and Windows - Nothing to really separate them here

• Viewing angles - again, nothing to really separate them

• Movies Overall - I've given the slight edge to the U2311H because of its better calibrated black depth and contrast ratio, which will help with shadow detail and darker scenes.

• Responsiveness - They are all very close really but I've given the very slight edge to the U2311H since its pale RTC overshoot was perhaps a little less noticeable than the U2312HM's darker overshoot. Very close call to be fair.

• Input lag - both are very low really but the U2312HM has the advantage with only 0.6ms average lag, compared with 10.6ms of the U2311H.

• Minimum luminance - The U2311H can reach a lower luminance than the U2312HM at 82 compared with 114 of the U2312HM. This might be more suitable for those working in darker lighting conditions or who are sensitive to brightness of screens.

• Colour accuracy Default - Out of the box the U2312HM had the very slight edge at dE average 2.2 compared with 2.4 of the U2311H.

• Colour accuracy calibrated - again very close and not really anything in it but the slight edge goes to the U2311H at 0.2 dE, as compared with 0.3 of the U2312HM.

• Calibrated Black depth - The U2311H wins comfortably here with a lower calibrated black depth of 0.14, compared with 0.17 of the U2312HM. A bit of a shame that black depth is not as good on the U2312HM as the new U2412M model.

• Calibrated Static Contrast Ratio - as a static number of 857:1, the U2311H is the best in this test. The U2312HM only managed 710:1 which is good for an IPS panel, but not great.

• Dynamic Contrast Ratio (DCR) - Neither really work at all, but the higher static CR of the U2311H means that DCR is 990:1, whereas the U2312HM's CR takes a hit when DCR is enabled and we only managed to measure a DCR of 595:1.

Overall there is not a huge difference between the new and the old model. Both ultimately offer the same features and specs with the only significant change being the move from CCFL to W-LED backlighting. To the end user this doesn't really signify a massive difference in real terms. The profile is a bit thinner and the power consumption should be a bit lower, but it doesn't really wow you or even matter in day to day situations. From a performance point of view there seemed to be a much better uniformity to the new model. Let's hope that extends to other samples and units as well as this could present a positive change which would impact the end user. There was nothing really to separate the two when it comes to colour accuracy and out of the box performance and the gaming responsiveness was also very similar. Input lag was very good on both but the 0.6ms average of the U2312HM was very impressive. The U2312HM did fall down a bit when it came to black depth and contrast ratio which was a shame, and the quite high minimum luminance could prove an issue to some potential buyers.

Taking everything into consideration the U2312HM does just seem to be a pretty even replacement for the U2311H. It has allowed Dell to move towards LED backlighting, and no doubt attract a new "generation" of buyers, but to be honest the overall performance and characteristics make them very similar. Not enough has changed to allow us to really say that the U2312HM has made a big improvement.

 
Exclusive discount for TFT Central readers
Quote "TFTPROMO" at checkout for �12 GBP (inc VAT) off your order.
Valid until 31st October 2011
 

Conclusion

The Dell U2312HM was pretty much everything we have come to expect from a Dell UltraSharp screen. It was pleasing to see Dell have stuck with an e-IPS panel and the decent feature and function set of the older model (U2311H) has been retained. The major technology change here is the move away from CCFL and towards a W-LED backlighting unit. In practical terms this only really offers the end user a slightly thinner profile and a slightly lower power consumption compared with the older screen. There are environmental advantages as well and it's a big trend at the moment so you can see why its been done with this model and others in their range.

From a performance point of view I was impressed in a couple of areas particularly. The input lag was incredibly low and basically this screen had no lag at all. Panel uniformity from our retail stock sample was also very good which was a positive sign considering there have been mixed reports and issues in the past with lower cost e-IPS screens. Let's hope other experiences are the same. Default colour setup was good as well, and responsiveness was very good, making it one of the faster 23" IPS models we have tested for sure. On the other hand I was a little disappointed by the quite low contrast ratio of 710:1 once calibrated. This was moderate for an IPS panel and not what we had hoped for considering what we had seen on other recent IPS screens, including the 24" U2412M.

The U2312HM is available now at a retail price of ~�210 (inc VAT). This is a little more expensive than a couple of other competing screens like the Asus ML239H (�180) and the LG IPS231P (�150). However the Dell brand, support and the feature set of the screen attracts this slightly higher price and it's still well worth a look in the 23" sector. It is still a considerable amount cheaper than some of the 24" IPS models, including Dell's own U2412M (�300) so if you don't mind sacrificing a little bit of screen real-estate and resolution this would be worth considering.

You can buy the Dell U2312HM now and get an exclusive discount of �12 GBP as a TFT Central reader. Visit www.pcbuyit.co.uk and quote "TFTPROMO" at checkout for �12 GBP (inc VAT) off your order. Valid until 31st October 2011.
 

Further reading: TestFreaks