Introduction

There's been a big influx of new gaming screens to the market over the last couple of years, with significant improvements coming in the form of 2560 x 1440 resolution TN Film panels, dynamic refresh rate technologies like NVIDIA G-sync and AMD FreeSync, and various blur reducing backlight techniques. All in the name of providing excellent LCD gaming experience. Previously fairly small players in the monitor market like Asus and Acer have emerged from the pack with exciting high end gaming specs and features attracting new buyers all the time.

Some mainstream and well-established manufacturers like Dell have generally stayed away from this fairly niche gaming market, in favour of producing a solid line-up of more general office and multimedia-type displays. A couple of years ago Dell pushed in to the more professional market with their high end UltraSharp range and they've invested more recently in UltraHD, 4K and 5k resolutions for their UltraSharp Premium (UP) range for very high end systems. Until now, Dell have still stayed away form the gaming market but that has just changed. They have just released their new S2716DG display, a model specifically aimed at gamers. It features a 2560 x 1440 resolution 27" panel based on TN Film technology, with a low 1ms G2G response time, 144Hz native refresh rate, G-sync support and even an ULMB (Ultra Low Motion Blur) mode. These are the kind of features being offered on high end gaming screens from the likes of Asus (ROG Swift PG278Q) and Acer (XG270HU) but this time under the popular Dell brand. This also goes hand in hand with their long-established support and warranty service which will help to attract new buyers for sure.

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Specifications and Features

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

The S2716DG offers a limited range of connectivity options given the use of a G-sync module. However, these have improved since the early G-sync capable screens released which only featured a single DisplayPort interface. This model offers DP 1.2a and an additional HDMI 1.4 input as well which is useful. The digital interfaces are HDCP certified for encrypted content and the video cables are provided in the box for DisplayPort only, along with a USB cable.

The screen has an internal power supply with the power cable you need in the box. There are also 4x USB 3.0 ports, 2 located on the back of the screen next to the video and power connections and 2 easy-access ports on the left hand side. There are also audio out and headphone ports offered (the latter on the left hand side of the screen for easy-access) but no further extras like card readers, ambient light sensors or human motion sensors provided as those are more aimed at office uses, while this is primarily a gaming screen.

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

OSD Menu

   
Above: OSD control buttons on the bottom edge of the screen. Click for larger version

All in all the menu was responsive and fairly easy and intuitive to navigate. The location of the buttons was a bit fiddly though and not as easy to use as some other screens. We suppose it's a sacrifice of the ultra-thin bezel design.

Power Consumption

In terms of power consumption the manufacturer lists a power on usage of 47.0W, and 0.5W in standby. We carried out our normal tests to establish its power consumption ourselves.

We tested this ourselves and found that out of the box the screen used 44.7W at the default 75% brightness setting. Once calibrated the screen reached 30.6W consumption, and in standby it used only 0.5W. We have plotted these results below compared with other screens we have tested.

We did notice an odd issue when the screen went to sleep (if set in Windows instead of a screen saver or anything like that). Normally with displays a simple move of your mouse or press of a keyboard button would wake the screen again quickly. However, on the S2716DG we noticed that this didn't seem to wake it. You could press one of the OSD control buttons on the monitor itself which would wake it up again, or cycle it off/on from the power button as well. This only happened when the screen was asleep and PC still running. If you put the whole PC in sleep mode (and therefore the screen would enter sleep mode), it would all come back on as normal when you woke the PC up again.

Panel and Backlighting

Panel Part and Colour Depth

The Dell S2716DG features an AU Optronics M270DTN01.5 TN Film panel which is capable of producing 16.7 million colours. While we do not have the full spec sheet for this particular panel, but we believe it to be a true 8-bit colour depth as with other recent 2560 x 1440 TN Film gaming panels (Asus ROG Swift PG278Q, BenQ XL2730Z). This is a new panel that we've not seen in any screen before.

The part is confirmed when dismantling the screen:

Screen Coating

The screen coating is a medium anti-glare (AG) offering. It isn't a semi-glossy coating, and isn't as light as some modern IPS type panels either. It's in keeping with other TN Film panels we've tested. Thankfully it isn't a heavily grainy coating like some old IPS panels feature, although there is some graininess noticeable. It retains its anti-glare properties to avoid too many unwanted reflections of a full glossy coating, but does not produce an too grainy or dirty an image that some thicker AG coatings can. There were some slight cross-hatching patterns visible on the coating as well but only if you looked very closely.

Backlight Type and Colour Gamut

The screen uses a White-LED (W-LED) backlight unit which has become very popular in today's market. This helps reduce power consumption compared with older CCFL backlight units and brings about some environmental benefits as well. The W-LED unit offers a standard colour gamut which is approximately equal to the sRGB colour space. Anyone wanting to work with wider colour spaces would need to consider wide gamut CCFL screens or the newer range of GB-r-LED type displays available now. If you want to read more about colour spaces and gamut then please have a read of our detailed article.

Backlight Dimming and Flicker

We tested the screen to establish the methods used to control backlight dimming. Our in depth article talks in more details about a common method used for this which is called Pulse Width Modulation (PWM). This in itself gives cause for concern to some users who have experienced eye strain, headaches and other symptoms as a result of the flickering backlight caused by this technology. We use a photosensor + oscilloscope system to measure backlight dimming control with a high level of accuracy and ease. These tests allow us to establish

1) Whether PWM is being used to control the backlight
2) The frequency and other characteristics at which this operates, if it is used
3) Whether a flicker may be introduced or potentially noticeable at certain settings

If PWM is used for backlight dimming, the higher the 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. The other factor which can influence flicker is the amplitude of the PWM, measuring the difference in brightness output between the 'on' and 'off' states. Please remember that not every user would notice a flicker from a backlight using PWM, 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.

100%                                                  50%                                                  0%
 
Above scale = 1 horizontal grid = 5ms

At 100% brightness a constant voltage is applied to the backlight. As you reduce the brightness setting to dim the backlight a Direct Current (DC) method is used, as opposed to any form of PWM. This applies to all brightness settings from 100% down to 0%. The screen is flicker free as a result, as advertised.

For an up to date list of all flicker-free (PWM free) monitors please see our Flicker Free Monitor Database.

Contrast Stability and Brightness

The brightness control gave us a very good range of adjustment. At the top end the maximum luminance reached 328 cd/m² which was only a little shy of the specified maximum brightness of 350 cd/m² from the manufacturer. There was a decent 289 cd/m² adjustment range in total, and so at the minimum setting you could reach down to a low luminance of 38 cd/m². This should be adequate for those wanting to work in darkened room conditions with low ambient light. A setting of 28 in the OSD menu should return you a luminance of around 120 cd/m² at default settings. It should be noted that the brightness regulation is controlled without the need for Pulse Width Modulation, using a Direct Current (DC) method for all brightness settings between 100 and 0% and so the screen is flicker free as advertised.

We have plotted the luminance trend on the graph above. The screen behaves as it should in this regard, with a reduction in the luminance output of the screen controlled by the reduction in the OSD brightness setting. This is pretty much a linear relationship as you can see.

The average contrast ratio of the screen was good for a TN Film panel with an average of 9241. This was mostly stable across the brightness adjustment range as shown above although it did seem to go a bit higher at 20% brightness and less.

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.

We restored our graphics card to default settings and disabled any previously active ICC profiles and gamma corrections. The screen was tested at default factory settings using our new X-rite i1 Pro 2 Spectrophotometer combined with LaCie's Blue Eye Pro software suite. An X-rite i1 Display Pro colorimeter was also used to verify the black point and contrast ratio since the i1 Pro 2 spectrophotometer 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 Performance and Setup

Default settings of the screen were as follows:

Dell S2716DG - Default Settings

  

Initially out of the box the screen was set in the default 'standard' preset. You could tell the screen was using a standard gamut backlight and the image looked reasonably good to the naked eye, but too bright for comfortable use. Colour balance felt pretty good, but the image appeared a bit washed out. We went ahead and measured the default state with the i1 Pro 2.

The CIE diagram on the left of the image confirms that the monitors colour gamut (black triangle) is roughly equal to the sRGB colour space. There is some over-coverage in some shades, particularly in blues and greens where it extends a fair way beyond the sRGB reference. It's not by anything major, but you may find some slight over-saturation in some colours. Default gamma was the main problem from a general-use point of view, being recorded at 1.9 average, leaving it with a big 15% deviance from the target. This is firmly a gaming screen though and perhaps it is a deliberate factory setup to achieve a brighter image for gaming. It's not the first gaming screen we've seen set up in this way. For desktop and other non-gaming uses we would like something closer to 2.2. The screen is lacking any gamma settings in the OSD menu so you are unable to alter the gamma without changing it at a graphics card level or through profiling with a calibration tool. That might be a pain for some users, although you may find it preferable at 1.9 anyway for gaming and you can try our calibrated ICC profile (see next section) as well which will hopefully help.

White point was a better story, being measured at 6617k and only ever so slightly too cool from the target of 6500k but with a low 2% deviance. The screen was set in the default 'standard' colour temp mode incidentally with RGB not available to tweak unless you enter the 'custom color' mode which we will do later for calibration.

Luminance was recorded at a very bright 266 cd/m² which is 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 without impacting any other aspect of the setup. The black depth was 0.29 cd/m² at this default brightness setting, giving us a good static contrast ratio (for a TN Film panel) of 920:1. Colour accuracy was an issue because of the low 1.9 gamma, with a dE average of 5.4 and maximum of 9.5 measured. Testing the screen with colour gradients revealed smooth gradients with some slight gradation in semi-dark tones and some fairly noticeable gradation evident in the darkest tones. Overall the screen is more set up for gaming needs as you might expect from a model like this, although you'll still need to tone down the brightness setting we expect. Getting it in to a better gamma for other uses is a bit more tricky without an actual gamma control in the main menu.

Calibration

We used the X-rite i1 Pro 2 Spectrophotometer combined with the LaCie Blue Eye Pro software package to achieve these results and reports. An X-rite i1 Display Pro colorimeter was used to validate the black depth and contrast ratios due to lower end limitations of the i1 Pro device.

Dell S2716DG - Calibrated Settings

   

All the OSD changes listed in the table above allowed us to obtain an optimum hardware starting point and setup before software level changes would be made at the graphics card level. We left the  LaCie software to calibrate to "max" brightness which would just retain the luminance of whatever brightness we'd set the screen to, and would not in any way try and alter the luminance at the graphics card level, which can reduce contrast ratio. These adjustments before profiling the screen would help preserve tonal values and limit banding issues as much as possible. After this we let the software carry out the LUT adjustments and create an ICC profile. The main thing we needed the software profiling stage to correct here would be the gamma curve, since we know that by default it was 1.9 average, and needed to be nearer to 2.2.

Average gamma was now corrected to 2.2 average, correcting the 15% deviance we'd seen out of the box. The white point was maintained at an accurate level, measured at 6502k (0% deviance) and correcting the minor 2% deviance we had out of the box. Luminance had been improved thanks to the adjustment to the brightness control and was now being measured at 119 cd/m². This left us a black depth of 0.14 cd/m² and maintained a good static contrast ratio (for a TN Film panel) of 876:1. Colour accuracy of the resulting profile was very good, with dE average of 0.6 now. Testing the screen with colour gradients revealed mostly smooth gradients with some minor gradation evident in darker tones as you see from most screens, and some minor banding introduced in the darkest tones due to the gamma correction at the graphics card level. Unfortunately this small level of banding is unavoidable when you need to correct gamma in this way through graphics card adjustments.

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.

Calibration Performance Comparisons

The comparisons made in this section try to give you a better view of how each screen performs, particularly out of the box which is what is going to matter to most consumers. When comparing the default factory settings for each monitor it is important to take into account several measurement areas - gamma, white point and colour accuracy. There's no point having a low dE colour accuracy figure if the gamma curve is way off for instance. A good factory calibration requires all 3 to be well set up. We have deliberately not included luminance in this comparison since this is normally far too high by default on every screen. However, that is very easily controlled through the brightness setting (on most screens) and should not impact the other areas being measured anyway. It is easy enough to obtain a suitable luminance for your working conditions and individual preferences, but a reliable factory setup in gamma, white point and colour accuracy is important and not as easy to change accurately without a calibration tool.

From these comparisons we can also compare the calibrated colour accuracy, black depth and contrast ratio. After a calibration the gamma, white point and luminance should all be at their desired targets.

Default setup of the screen out of the box was ok for gaming needs, but really fairly poor for more general day to day office-type uses. The white point was close to the 6500k target at least, but the main issue with the screen was the 1.9 gamma. Like we say, fine for gaming really, and perhaps preferred in some cases, but we'd have liked some control over the gamma from the screen to get it nearer to 2.2 for other uses. This had a knock-on effect to the dE colour accuracy measurements as well. The contrast ratio was good for a TN Film panel at least. The S2716DG was actually fairly similar to the BenQ XL2730Z and Acer XG270HU which also had a 1.8 - 1.9 default gamma and poor dE. The take away from this is that the screen is set up for gaming out of the box, and so for other uses it will need some tweaking ideally.

The display was ok when it came to black depth and contrast ratio for a TN Film panel. With a calibrated contrast ratio of 876:1 it was comparable to some of the other TN Film screens we've tested, like the Acer XG270HU (828:1), Asus ROG Swift PG278Q (858:1) and BenQ XL2730Z (917:1). It was not quite as high as some modern IPS-type panels like the Dell U2515H (1138:1) for instance, or more gamer orientated IPS offerings like the Acer XB270HU (1000:1) or Asus ROG Swift PG279Q (989:1). Of course none of these IPS screens can compete with VA panel types which can reach over 2000:1 easily, and even close to 5000:1 in the case of the 24" Eizo FG2421 shown here.

Viewing Angles

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

Viewing angles of the screen were as you might expect from a TN Film panel. Unfortunately this panel technology is inherently poor in this field, and so viewing angles are more restrictive than other competing technologies like IPS and VA variants. Although the manufacturer will quote a viewing angle of 170 / 160 (a classic indication that a TN Film panel is being used by the way if in doubt), in practice there are some obvious contrast and colour tone shifts horizontally, and especially vertically.

As you move your head from side to side in a horizontal plane, there is a contrast shift and the image becomes darker and introduces a slight green/yellow hue. As you move to a wider angle the image can become more washed out as well. Vertically the fields of view are more restrictive still. From above the image becomes pale and washed out, while from below there is a characteristic TN Film darkening of the image. Unfortunately vertically the viewing angles will introduce noticeable shifts in the contrast and colour tone of the image which mean that for any colour critical work it is not really very well suited. TN Film panels have long suffered from these restrictive viewing angles due to the nature of their pixel structure. They are still fine for a single user for general use and certainly the TN Film panels offer their advantages when it comes to pixel response times and refresh rate for gaming. If however, you were hoping to do any colour critical or photography work you may find these shifts in the appearance of the image difficult. An IPS-type panel would probably be a wiser choice if you were looking for a screen with much wider viewing angles but having said that you are probably mainly interested in gaming if you are considering this screen. Remember, the S2716DG is specifically designed for gaming, and so you will have to live with some of the sacrifices of TN Film to get the kind of gaming performance and features offered here. There are some high refresh rate gaming IPS panels available now as well which can offer better viewing angles than TN Film models, although they are normally priced higher and have some other characteristic differences, and so TN Film models like this still have their place for many users.

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

On a black image there is a moderate pale grey tint introduced to the image when viewed from a wide angle. This isn't too severe and shouldn't present any real problems in practice. Certainly not the obvious white glow you get from most modern IPS-type panels in similar situations and fairly standard for a TN Film panel. Very similar to what we have seen from other recent gaming screens like the Asus ROG Swift PG278Q and BenQ XL2730Z. The glow you see from most modern IPS panels, including the high refresh rate IPS models like the Asus ROG Swift PG279Q and Acer XB270HU can put off some users. So on the one hand, those IPS models have much better general viewing angles than the TN Film models, but they do show more glow which some people find an issue.

Panel Uniformity

We wanted to test here how uniform the brightness was across the screen, as well as identify any leakage from the backlight in dark lighting conditions. Measurements of the luminance were taken at 35 points across the panel on a pure white background. The measurements for luminance were taken using BasICColor's calibration software package, combined with an X-rite i1 Display Pro colorimeter with a central point on the screen calibrated to 120 cd/m². The below uniformity diagram shows the difference, as a percentage, between the measurement recorded at each point on the screen, as compared with the central reference 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 screen was good with only the left hand and bottom edges showing any real significant variation. Here the backlight was a little darker, down by about 19% maximum in the worst cases (top left hand corner = 101 cd/m²). Overall the uniformity was good, with 71% of the screen with a 10% deviance from the centrally calibrated point.

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. The camera showed there was some clouding detected along the lower edge of the screen and in the bottom right hand corner but it was very slight.

Note: if you want to test your own screen for backlight bleed and uniformity problems at any point you need to ensure you have suitable testing conditions. Set the monitor to a sensible day to day brightness level, preferably as close to 120 cd/m² as you can get it (our tests are once the screen is calibrated to this luminance). Don't just take a photo at the default brightness which is almost always far too high and not a realistic usage condition. You need to take the photo from about 1.5 - 2m back to avoid capturing viewing angle characteristics, especially on IPS-type panels where off-angle glow can come in to play easily. Photos should be taken in a darkened room at a shutter speed which captures what you see reliably and doesn't over-expose the image. A shutter speed of 1/8 second will probably be suitable for this.

General and Office Applications

The S2716DG feature a large 2560 x 1440 WQHD resolution which is still pretty rare for gaming 27" screens. There's only been a few released so far with TN Film panels - the Asus ROG Swift PG278Q, Acer XG270HU and the BenQ XL2730Z. So in this space there's still a limited choice when it comes to high resolution gaming screens based on this technology, with most other models still offering only 1920 x 1080. This extra resolution is excellent both for gaming and for other uses.

The pixel pitch of 0.233 mm is quite small as a result though, 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 resolution 27" models offer a tight pixel pitch and therefore small text as well. We found it quite a change originally coming from 21.5 - 24" sized screens back in the day, even those offering quite high resolutions and small pixel pitches. Although now we are very used to working with 27" 1440p screens all the time and find them very comfortable and a significant upgrade over 1080 / 1200p models. Some users may find the small text a little too small to read comfortably, and we'd advise caution if you are coming from a 19" or 22" screen for instance where the pixel pitch and text are much larger. The extra screen size takes some getting used to over a few days as there really is a lot of room to work with but once you do, it's excellent. For those wanting a high resolution for their work, this is a really good option. The image was very sharp and crisp and text was very clear. With its WQHD display, you enjoy 77% more desktop space than a full HD screen to spread out your windows and palettes.

The frameless thin bezel design mean that the S2716DG could be easily integrated into a multi-screen set up if you wanted. The moderate AG coating of the TN Film panel could be considered a bit grainy, especially on white office backgrounds to a lot of people. It's not as clear as modern IPS coatings or any semi-glossy solution. Still, it's not as grainy as old IPS panels and is on par with other TN Film matrices we've tested. Perhaps the main issue with this panel technology though is the restrictive viewing angles, making contrast and colour tone shifts a bit of a problem when it comes to colour critical work. They are the same here as other TN Film panels, being restrictive especially vertically. The screen is fine when viewed head on though really for office and text work, but for colour critical work or photo editing etc you'd be better off with an IPS-type panel. The default setup of the screen was a bit restrictive for normal uses, as the gamma is set up more for gaming, and hard to adjust without a calibration tool (or maybe our calibrated ICC profile).

The brightness range of the screen was very good, with the ability to offer a luminance between 328 and 38 cd/m². This should mean the screen is perfectly useable in a wide variety of ambient light conditions, including darkened rooms. A setting of ~28 in the OSD brightness control should return you a luminance close to 120 cd/m² out of the box. On another positive note, the brightness regulation is controlled without the need for the use of the now infamous Pulse-Width Modulation (PWM), and so those who suffer from eye fatigue or headaches associated with flickering backlights need not worry.

There was a very feint audible whine from the screen but you really had to press your ear up to the top of the screen to notice it. The screen remains fairly cool even during prolonged use. There are some extras offered on this screen with audio out, headphone socket and 4x USB 3.0 ports provided. There isn't anything else like an ambient light sensor or card reader which can be useful in office environments. This is primarily a gaming screen remember. There was a good range of ergonomic adjustments from the stand though, and it's good to see Dell haven't reverted to a more basic stand as they have with some multimedia models in the past.

 
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 a 144Hz native refresh rate. However, if you want you are able to run the screen outside of this resolution. We tested the screen at a lower 1920 x 1080 resolution to see how the screen handles the interpolation of the resolution, while maintaining the same aspect ratio of 16:9. At native resolution the text was very sharp and clear. When running at a 1080p resolution the text is still reasonably clear, with moderate levels of blurring. You do lose a lot of screen real-estate as well of course but the image seems to be quite well interpolated if needed.

Gaming Introduction

The S2716DG is aimed at a gaming audience primarily. The new screen offers you a 2560 x 1440 resolution TN Film panel which until about 15 months ago was not offered in the market. Now we've seen a few 1440p TN Film gaming screens emerge, and the extra resolution compared with 1080p is certainly a welcome upgrade. This TN Film panels also offers a native 144Hz refresh rate and 1ms G2G rated response time, so is of course an ideal option for fast moving content. This has then been combined with NVIDIA G-sync for the benefits of dynamic refresh rate control. This is particularly important given the added resolution here, as the demands on your system running games at 1440p @ 144Hz are very high.

There is also the accompanying ULMB blur reduction mode provided here. This allows for a strobing backlight to reduce perceived motion blur in dynamic content. Have a read of our blur reduction backlight article which talks about the benefits of these kind of technologies in more detail. It's a feature some people really like when it comes to dynamic content, primarily gaming. It can really help reduce the motion blur you see on the screen due to the way LCD technology operates. As with other screens which support ULMB, it cannot be used at the same time as G-sync since that operates with a dynamic refresh rate by its nature. You can enable ULMB if you would rather use that to G-sync when your screen is set to 85, 100 or 120Hz refresh rates. It does not work at 144Hz refresh rate. We will look at the ULMB operation in more detail later. Although NVIDIA G-sync is offered here, NVIDIA 3D Vision is not supported unfortunately.

Correction 19/2/16 - PCmonitors.info have confirmed that the screen does support 3D Vision after all!

It should be noted that this model is TN Film based, and so can't offer the all-round performance in other areas that the new wave of fast IPS panels (Acer Predator XB270HU, Asus ROG Swift PG279Q etc) can offer. We have made some of those comparisons elsewhere in this review.

Responsiveness and Gaming

The S2716DG is rated by Dell as having a 1ms G2G response time, which indicates the panel uses overdrive / response time compensation (RTC) technology to boost pixel transitions across grey to grey changes. There is user control over the overdrive impulse within the OSD menu using the 'Response Time' option, with the 1ms spec supposedly relating to the fastest mode available ("fast"). The part being used is the AU Optronics M270DTN01.5 TN Film panel. Have a read about response time in our specs section if you need additional information about this measurement.

We will first test the screen using our thorough response time testing method. This uses an oscilloscope and photosensor to measure the pixel response times across a series of different transitions, in the full range from 0 (black) to 255 (white). This will give us a realistic view of how the monitor performs in real life, as opposed to being reliant only on a manufacturers spec. We can work out the response times for changing between many different shades, calculate the maximum, minimum and average grey to grey (G2G) response times, and provide an evaluation of any overshoot present on the monitor.

We use an ETC M526 oscilloscope for these measurements along with a custom photosensor device. Have a read of our response time measurement article for a full explanation of the testing methodology and reported data.

Response Time Setting Comparison

The S2716DG comes with a user control for the overdrive impulse available within the OSD menu in the 'display' section. There are 2 options available here under the 'Response Time' setting. First of all we carried out a fairly small set of measurements and motion tests in both settings for the purposes of identifying which was the optimum response time setting. There tests were conducted at 144Hz refresh rate.

Firstly we tested the response times with the setting at the default 'normal'. Response times measured here were fast, with an average of only 2.8ms G2G. There was some moderate levels of overshoot introduced on a couple of transitions here, but overall it was at low levels. Motion clarity tests revealed smooth movement and no obvious dark or pale trailing, which could be caused by high overshoot. Some users have reported some artefacts on white backgrounds which is down to the overshoot seen on some transitions to white it seems.

Pushing the response time setting up to the maximum 'fast' setting improved the overall response time measurements a little, now at 2.2ms G2G. However, it was at the cost of very high levels of overshoot which are very obvious in practice as well. This mode should be avoided, stick to 'normal'.

Refresh Rate

We tested the response time behaviour in the optimum "normal" setting at a variety of refresh rates. We know form past experience with other displays that the response time behaviour can sometimes change at different refresh rates. With this screen supporting G-sync, the dynamic refresh rate could therefore influence in theory the response times if they were to vary much across the refresh frequencies.

Here we have measurements at 60Hz and 144Hz:

60Hz Refresh Rate

144Hz Refresh Rate

There was little difference in response times it seemed, as even at 60Hz they were very fast (3.4ms G2G). There did appear to be some slight improvement as you pushed the refresh rate higher, where they reached 2.8ms G2G average at 144Hz. It's not a huge difference, and the screen is still very fast at lower refresh rates. This should mean that even if you're running at lower refresh rates, for instance from an external console or device, then the pixel transitions are still very fast here which is good news.

Interestingly the overshoot behaviour varied at different refresh rates for some reason. Some transitions showed some overshoot at moderately high levels when running at 60Hz (e.g. the 0 - 255 transition, 12.1% overshoot), but at 144Hz that had disappeared. On the other hand, transitions such as 150 - 255 showed low levels of overshoot at 60Hz (5.7%) but higher levels at 144Hz (13.2%). All in all, it levelled out pretty much but it seemed the G-sync module did dynamically control the overdrive impulse at differing refresh rates, and with some slightly different characteristics as you went when it came to overshoot. The overall overshoot in this normal response time mode was low anyway so it wasn't really an issue, just something interesting to note about the behaviour of the overdrive impulse.

The higher you can run the screen the better though, as there is some small benefit in response times it seems, not to mention obvious improvements in frame rates and perceived fluidity / motion clarity as a direct result of the increased refresh rate. Also, while the overshoot % remained pretty similar overall, the duration of the overshoot was reduced as you increased the refresh rate due to the additional frames being pushed to the screen.

The below graphs show as an example the changing overshoot behaviour for the 0 - 255 transition as you increase the refresh rate from 60Hz up to 144Hz. You will see the peak at the top reduces down to nothing with the change in refresh rate:

60Hz refresh rate (scale = 20ms)

100Hz refresh rate (scale = 20ms)

120Hz refresh rate (scale = 20ms)

144Hz refresh rate (scale = 20ms)

More Detailed Measurements
Response Time setting = Normal, 144Hz Refresh Rate

Having established that the normal setting offered the best response/overshoot balance we carried out our normal wider range of measurements as shown below. We used the maximum refresh rate of 144Hz.

The average G2G response time was more accurately measured at 3.1ms which was excellent. Transitions were pretty stable across all the changes, whether they were changes from dark to light (rise times) or from light to dark (fall times). The fall times were a little faster. Some transitions did reach down to the specified 1ms G2G as well, even at this normal response time setting.

There was some moderate levels of overshoot at this setting, particularly it seemed on changes to white (x > 255) where there was overshoot up to 27.4% maximum. Overall there were only a few transitions where it was noticeable and most transitions showed very low levels of overshoot. Not too bad although perhaps a slightly less aggressive overdrive impulse would have been preferred to cut back the overshoot completely, even at the cost of slightly slower response times.
 

Display Comparisons

The above comparison table and graph shows you the lowest, average and highest G2G response time measurement for each screen we have tested with our oscilloscope system. There is also a colour coded mark next to each screen in the table to indicate the RTC overshoot error, as the response time figure alone doesn't tell the whole story.

Overall the responsiveness of the S2716DG was very comparable to some of the best TN Film gaming screens we've tested. With a 3.1ms G2G average and low/moderate overshoot, it was perhaps ever so slightly better than the excellent Asus ROG Swift PG278Q and BenQ XL2730Z which showed slightly more overshoot than the Dell if you refer to those reviews. There was very little in it, but there was just slightly less apparent trailing on the Dell we felt. These models are a bit faster than the high refresh IPS panels available, which reach down to about 5ms G2G average in our tests, although those are free from any noticeable overshoot. Some users prefer the "feel" of the TN Film panels and their fluidity, and combined with a 144Hz refresh rate and G-sync you have a lovely, smooth gaming experience here. If you enable ULMB instead you also get a very low level of perceived motion blur and improved image clarity on moving scenes.

The screen was also tested using the chase test in PixPerAn for the following 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 comparison between different screens and technologies as well as a means to compare those screens we tested before the introduction of our oscilloscope method.

27" 1ms G2G AU Optronics TN Film @ 144Hz (Response Time = Normal)

In practice the Dell S2716DG performed best with the response time setting at normal. There were low levels of blurring evident, the image looked sharp and there were only low levels of overshoot detected. You can see some slight dark trailing in places behind the moving speech bubble for instance. The support for higher refresh rates up to 144Hz provided additional levels of motion clarity and image smoothness which surpassed what was possible from 60Hz panels. The additional G-sync support for NVIDIA users will also be of real benefit.

27" 1ms G2G AU Optronics TN Film @ 144Hz (Response Time = Normal)


27" 1ms G2G AU Optronics TN Film @ 144Hz (OD = Normal)

27" 1ms G2G AU Optronics TN Film @ 144Hz (AMA = High)

27" 1ms G2G AU Optronics TN Film @ 144Hz (OD =  Normal)

The above then compares the S2716DG with a few other popular TN Film based gaming models, all with 2560 x 1440 resolution and 144Hz refresh rate. You will see the comparison first of all against the very popular Asus ROG Swift PG278Q TN Film model and then the similarly fast BenQ XL2730Z and Acer XG270HU displays. The Asus and BenQ models are very similar overall to the Dell, with perhaps a slightly more noticeable overshoot in places. The Acer was a tiny bit slower but was free from any obvious overshoot. In practice, you'd be hard pressed to notice much real difference between the 4 models here.

27" 1ms G2G AU Optronics TN Film @ 144Hz (Response Time = Normal)

27" 4ms G2G AU Optronics AHVA (IPS-type) @ 144Hz (OD = Normal)

27" 4ms G2G AU Optronics AHVA (IPS-type) @ 144Hz (OD = Normal)

27" 4ms G2G AU Optronics AHVA (IPS-type) @ 144Hz (Trace Free = 80)

The above images compare the S2716DG then with the three high refresh rate IPS-type panels we've tested. In practice the IPS models show smooth and fluid movement and are also free of any noticeable overshoot as well which is pleasing. The TN Film models like the Dell S2716DG are slightly faster, and have a slightly different "feel" than the IPS models, but most users would be perfectly happy with any of the options here for gaming.

Ultra Low Motion Blur (ULMB)

The Dell S2716DG also features an integrated Blur Reduction Backlight system, dubbed "Ultra Low Motion Blur" (ULMB). This is linked to the G-sync module and is provided on most G-sync enabled screens that have a native high refresh rate. We have already seen a lot of positive improvements in perceived motion blur from such systems in the past. Our in depth article from June 2013 (updated 17 March 2015) looked at this in a lot more detail, and tested some of the original LightBoost "hacks" to achieve a strobed backlight and blur reduction benefits. Since then we've seen a quite a lot of monitors integrate a strobed backlight with simple user control from the menu and with better implementation than LightBoost methods.

The ULMB feature is accessible from the 'display' section of the OSD menu. It is only available when running the screen at 85, 100 and 120Hz modes. It is not available at 144Hz, and it is also important to note that ULMB does not work when you are using G-sync, it's one or the other. When you enable the ULMB feature a new option appears for the "Pulse Width" which allows you to control the duration of the backlight strobes. A shorter "on" period can help reduce perceived motion blur even more, but at the cost of screen brightness. You can adjust this between 100 and 10, and as you lower the setting the screen also becomes progressively darker as you reduce the "on" period of the strobe. Nice to see this included as an option within the menu for those who like to play around with the setting, much like you could do by adjusting LightBoost levels on older models using the "hack" method. There is no control to adjust the timing of the strobe to impact the strobe cross-talk it can introduce, so we will have to hope that the default timing setup is suitable.

Operation - 85Hz

ULMB backlight cycling, 85Hz (scale = 5ms)
pulse width setting= 100

We measured the screen using our oscilloscope when viewing a solid white image, with ULMB feature turned on and with refresh rate set at 85Hz. This is the lowest refresh rate at which you can operate the ULMB mode. As a reminder, it works at 85, 100 and 120Hz only. We left the pulse width (strobe length) setting at 100 initially. Normally the oscillograph would show a flat straight line when measuring a static white image (as no PWM is being used for backlight dimming), but here the ULMB feature is cycling the backlight off and on rapidly.

The time for each complete cycle is 11.76ms which shows that in this case the backlight is being cycled at the same frequency as the refresh rate, 85 times per second. The strobe is in time with the refresh rate of 85Hz.
 

Operation - 100Hz

ULMB backlight cycling, 100Hz (scale = 5ms)
pulse width setting = 100

When running the screen at a 100Hz refresh rate the behaviour is exactly the same. The only difference is that the strobe is now synced with the new refresh rate, with a new strobe every 10ms (100 times per second).

Operation - 120Hz

ULMB backlight cycling, 120Hz (scale = 5ms)
pulse width setting = 100

Again when set at 120Hz refresh rate the strobes are in sync again, with a new strobe every 8.33ms (120 times per second). The above is with pulse width at the default 100. We can also see what impact on the strobing it has if you lower the pulse width setting.

ULMB backlight cycling, 120Hz (scale = 5ms)
pulse width setting = 50

ULMB backlight cycling, 120Hz (scale = 5ms)
pulse width setting = 10

As you reduce the pulse width setting you are adjusting the 'on' period of the strobe, shown by the top portion of each peak. As you reduce the setting the strobe 'on' time gets progressively shorter as you can see from the above 2 graphs, the first at a setting of 50 and the second at a setting of 10 (the minimum setting available). This impacts the perceived blur somewhat, with the shorter 'on' times resulting in a clearer image. At the same time though the brightness of the image is affected and it becomes very dark, the lower you go with the setting. More on that in a moment. There will be a point where the user does not see any further benefit to their eyes of reducing the strobe length further, but you can have a play around with the setting to find your personal preference to balance perceived motion blur and brightness of the image.
 

Pulse Width Setting - Strobe Length

We measured the strobe length at a variety of the Pulse Width settings, while running at the maximum 120Hz refresh rate mode. You can adjust the setting in steps of 1 incidentally. Each complete strobe lasts a total of 8.33ms (120 strobes per second). This strobe timing was exactly the same as we'd seen on other ULMB-enabled monitors at 120Hz including the Asus ROG Swift PG278Q and PG279Q for instance and so is likely fixed for the NVIDIA ULMB feature at this refresh rate.

Pulse Width Setting - Brightness Range (120Hz)

We tested the brightness output of the screen when ULMB was turned on at 120Hz. You can independently control the brightness setting as well if you want, but we left it at the default 100 and just changed the pulse width (PW) strobe length setting to establish the brightness range when using this option. With the PW setting at 100 the maximum achievable luminance of the screen was a moderate 118 cd/m². This should be enough for a lot of uses, but you cannot get a brighter display when using ULMB if you wanted to. This is a typical performance from a strobe backlight anyway and represented a decent enough luminance level. You can achieve a slightly brighter display if you use the feature at 85 or 100Hz since the strobes are less frequent, but it's not a significant amount.

As you reduce the PW setting the luminance drops significantly, at the lowest setting probably being far too dark for any practical use. At least you can control a reasonably wide range here, so you can find a level which suits your needs. We suspect a setting of 100 will probably be adequate for most normal users anyway, as the ULMB mode certainly brings about positive improvements to the perceived motion blur.

Brightness Range (PW at 100, 120Hz)

We also wanted to test the brightness range when leaving PW at its default 100, and changing the brightness control of the screen instead. This leaves the strobe behaviour alone, operating as it does with PW at 100, and instead just dims the backlight. The table above confirms the range available through that control. You can achieve a slightly brighter display if you use the feature at 85 or 100Hz since the strobes are less frequent, but it's not a significant amount.

One annoying thing relating to the brightness control became apparent as you switched ULMB on and off. When you first turn ULMB on, the brightness level of the backlight remains as it was set before. So while you might be using something around 28% brightness for a moderate desktop brightness normally, when you turn ULMB you will almost certainly want to have brightness at 100%. The brightness control is not separate for ULMB on/off sadly. So you find yourself having to move the brightness control up to 100% then. When you turn ULMB back off, the brightness setting stays at 100% in the menu, but actually the brightness doesn't jump all the way up to the maximum brightness level. It seems to level out at a random ~92 cd/m² ish. When you then change the brightness setting in the OSD menu, even by 1% down to 99%, it jumps back to the "correct" brightness it would be normally. A bit of an odd bug with the brightness level really when turning ULMB on and off.

Maximum Blur Reduction Brightness - Display Comparison

For ease of reference we have also provided a comparison table below of all the blur reduction enabled displays we've tested, showing their maximum luminance before blur reduction is turned on (normal mode) and their maximum luminance with the feature enabled. This will give you an idea of the maximum brightness you can expect from each model when using their blur reduction feature, if that is important to you. A lot of people want a brighter display for gaming and sometimes the relatively low maximum luminance from blur reduction modes is a limitation.

These comparisons are with the refresh rate as high as is available for the blur reduction feature to function. For most this is at 120Hz, but some also support the feature at higher. You can achieve a slightly brighter display if you use the feature at 85 or 100Hz since the strobes are less frequent, but it's not a significant amount. That can also introduce more visible flicker in some situations.

Note: Pulse Width setting at max where applicable.
*Note 2: The Acer XB270HU was later updated to include a 120Hz mode, which will produce a slightly darker maximum luminance
 

Colour and Other Setup Characteristics

We wanted to test the impact on the setup of the screen when enabling the ULMB feature to see whether it has a knock-on effect to white point, gamma or colour accuracy. You can see straight away that it impacts the luminance of the screen, which we've already looked at above.

Dell S2716DG - Calibrated Settings, ULMB Off

   

Above is our calibrated state from earlier on in the review, with the ULMB feature turned off.

Dell S2716DG - Calibrated Settings, ULMB On

We turned the ULMB mode on, but left the PW option at 100 here, and with the default maximum 100 brightness as well. We left our calibrated ICC profile active from our initial calibration to see what immediate impact the ULMB setting had on the colour performance. The gamma and white point were skewed slightly here, with gamma now a little higher at 2.3 average (7% deviance), and white point being a little cooler at 6680k (3% out). The contrast ratio remained similar at 831:1. The colour accuracy was also a little off with average dE of 1.6 now, maximum of 2.88. No major impact really to the appearance of the screen of the colour rendering other than the reduction in achievable luminance of course. This was pleasing as we know from testing older LightBoost strobed backlight systems that they can really impact the colours and white point of a screen when enabled.

Blur Reduction Tests

Of course the main thing we want to test is what improvements the Blur Reduction mode offers when it comes to motion clarity and gaming. We were pleased with the results we'd seen from LightBoost backlights when we tested them, and also from the natively supported blur reduction feature on other displays including the other popular TN Film gaming models we've tested.

We were very pleased with the results here as we had been on other blur reduction displays, with an obvious and marked improvement in perceived motion blur experienced. Tracking of moving objects became much easier and the image looked sharper and clearer. We used the BlurBusters full-screen TestUFO online motion test (all ULMB supported refresh rates) as well to put the feature through its paces and were pleased with the results. The upper half of the screen was a little clearer than the bottom, and in the bottom third of the screen some strobe cross-talk became apparent. It is impossible to eliminate strobe cross-talk completely due to the way they operate, but the important thing is whereabouts on the screen this manifests itself and to what level. The central region is probably the most important since that's where a lot of your gaming focus will be, where crosshairs and the likes are. We were pleased that there was minimal cross-talk here in the central region and the image looked very good. Having the ability to alter the strobe length through the PW setting was also very useful, and you could tweak it to your preference to reduce even more of the persistence if you wanted, as long as you didn't mind sacrificing some brightness.

Another very good implementation of a strobe backlight system here, we were impressed. We suppose the only minor quibble is the inability to operate the feature at 144Hz or in an ideal World, at the same time as using G-sync.

Additional Gaming Features

Lag

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.

(Measurements in ms)   Total Display Lag (SMTT 2) 4.25 Pixel Response Time Element 1.55 Estimated Signal Processing Lag 2.70 Lag Classification 1

Class 1

We have provided a comparison above against other models we have tested to give an indication between screens. The screens tested are split into two measurements which are based on our overall display lag tests (using SMTT) and half the average G2G response time, as measured by the oscilloscope. The response time is split from the overall display lag and shown on the graph as the green bar. From there, the signal processing (red bar) can be provided as a good estimation.

The screen showed a total lag of only 4.25ms. Approximately 1.55ms of that can be accounted for by pixel response times, leaving an estimated signal processing lag of only 2.7ms. This is basically nothing and means the screen should be fine for all levels of gaming. Other G-sync screens to date have shown similar very low levels of lag which is pleasing. This remains consistent at all refresh rates, and also when using ULMB.

Movies and Video

The following summarises the screens performance in video applications:

• 27" screen size makes it a reasonable option for an all-in-one multimedia screen, much smaller than LCD TV's and many larger format desktop monitors which are now emerging.

• 16:9 aspect ratio is well suited to videos and movies, leaving you with smaller/no borders on DVD's and wide screen content at the top and bottom than on a 16:10 aspect display.

• 2560 x 1440 resolution can support full 1080 HD resolution content.

• Digital DisplayPort interfaces support HDCP for any encrypted and protected content

• DisplayPort and HDMI connections available which is an improvement over older G-sync screens. The addition of HDMI is certainly welcome for connecting external devices and Blu-ray players.

• Cable provided in the box for DisplayPort only.

• Moderate AG coating provides reasonably clear images with no major graininess, and without the unwanted reflections of a glossy solution. Some graininess apparent as with other TN Film panels, but shouldn't present a problem in movies.

• Wide brightness range adjustment possible from the display, including high maximum luminance of ~328 cd/m² and a good minimum luminance of 38 cd/m². This should afford you very good control for different lighting conditions. Contrast ratio remains stable across the adjustment range as well and is good for a TN Film panel. Brightness regulation is controlled without the need for PWM and so is flicker free at all settings which is pleasing.

• Black depth and contrast ratio are good for an TN Film panel at 876:1 after calibration. Detail in darker scenes should not be lost as a result.

• There is no specific 'movie' preset mode available sadly only the standard mode which you might have to keep changing for differing uses perhaps.

• Very good pixel responsiveness which can handle fast moving scenes in movies without issue. Low to moderate overshoot issues when sticking to the 'normal' response time mode which is good.

• Although it has 120Hz+ refresh rate support it does not support NVIDIA 3D Vision.

• Viewing angles are limited due to the use of TN Film panel technology. May cause issues with gamma and contrast shift if you change your line of sight or have several people trying to see the screen at once. Not really an ideal technology for movies as a result of this viewing angle limitation.

• No real backlight leakage on our sample which is good.

• Wide range of ergonomic adjustments available from the stand, allowing you to adjust the screen to suit varying viewing positions.

• No integrated stereo speakers offered on this model but there is an audio out and headphone connection.

• No hardware aspect ratio options on this screen, but graphics card can handle the scaling if using a PC. For external devices the native 16:9 format should mean most things aren't too much of an issue anyway.

• Picture By Picture (PbP) or Picture In Picture (PiP) are not available on this model.
  
   

Conclusion

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It was really good to see a new gaming-focused screen from Dell, a manufacturer who have been known for producing quality displays and offering excellent support and warranties over the years. They've branched out from their more mainstream and multimedia displays, and their first proper venture in to the gaming arena has been a success we think. We liked the design of the new model, with a very thin bezel design, sleek appearance and quality build. The stand is also very good and the connectivity was adequate (limited by G-sync), with a few nice extras like the USB ports and audio connections.

Performance-wise the main area of interest is in gaming performance, and it doesn't fail to deliver here. The response times are very fast and it's certainly on par with other very popular TN Film gaming options from the like of Asus, Acer and BenQ. The 144Hz refresh rate is obviously a huge benefit, and the combination with NVIDIA G-sync makes the whole experience even better. That's particularly important when you consider the boosted resolution here and the demand that will have on your graphics card. The higher resolution is a benefit in itself especially when you look outside of gaming applications. We were also pleased to see ULMB included here which brought about the usual excellent benefits when it comes to blur reduction. The lag was also non-existent, in line with other G-sync models we've tested. The only real negative when it came to gaming was the weird brightness control when switching ULMB on and off that we've talked about in the review.

Away from gaming the screen fell a bit short we felt in some areas. The default setup was aimed at gaming, but left us with a low gamma for other day to day uses, and difficulty changing that without a calibration device. We would have also liked to see some preset modes offered so we could set one up for general use and another for gaming. The screen was also limited by the TN Film technology in some areas, particularly viewing angles but that is the same as other TN Film models around and should be a known sacrifice really. Overall it's a very solid gaming screen and provides an interesting alternative to the lesser-established brands out there if you want something from a long-standing, proven manufacturer.