Dell P2416D

Responsiveness

Input lag

A small tool called SMTT 2.0 was used alongside a sensitive camera to compare the latency of the P2416D with a number of monitors with known input lag values. Using this method and taking over 30 repeat readings, we calculated 4.85ms (under 1/3 of a frame) of input lag. This value reflects both the element of input lag that you see (pixel responsiveness) and that which you feel (signal delay). This is indicative of a very low signal delay which shouldn’t cause a bottleneck for any user.

Perceived blur (pursuit photography)

Our article on responsiveness takes a look at various factors affecting the responsiveness of a monitor. One of the key concept explored is perceived blur, and how the movement of your own eyes is actually a significant contributor to that. One which, in fact, masks a lot of what the pixel responses of the monitor are doing. By using what’s known as ‘pursuit’ photography, mentioned in the article, it’s possible to accurately capture motion on a monitor in a way that reflects what the eye would see when tracking motion. A moving camera is used to capture static images, revealing the perceived blur that would be caused by eye movement as well as any trailing or inverse ghosting (overshoot) on top of that.

The following images are pursuit photographs taken using the UFO Motion Test for ghosting. The test is running at 960 pixels per second, which is a good practical speed for such photography that shows what it needs to. The middle row of the test (medium cyan background) was used here, with the monitor set to both ‘Normal’ and ‘Fast’ for its ‘Response Time’. We also captured the performance at 75Hz, which the monitor will do comfortably at its native resolution as we’ll come onto a little later. The bottom image shows a fast 60Hz reference, a Samsung S27A750D set to full brightness (to eliminate PWM and associated artifacts) and using its ‘Faster’ response time setting, optimal for 60Hz. This reference screen essentially shows what things should look like at 60Hz where pixel responses are not a limiting factor.

Perceived blur with various settings

With ‘Response Time’ set to ‘Normal’ you can see a little bit of trailing from slower than optimal pixel response times, but this is certainly a minor factor compared to the blur caused by eye (camera) movement). Using the ‘Fast’ setting replaces this additional trailing with a bright inverted trail (inverse ghosting or overshoot), due to the grey to grey acceleration being overly aggressive. It is clear from this analysis and when actually using the monitor that ‘Normal’ provides the best balance, as ‘Fast’ introduces obvious and unsightly artifacts that are widespread and will irritate some users. In our subsequent analysis, we keep the monitor in its ‘Normal’ (default) state for ‘Response Time’ and analyse perceived blur over a broad range of pixel transitions.

We also tested the monitor at 75Hz using the optimal ‘Normal’ setting. This reduced the perceived blur compared to running the monitor at its default 60Hz. There is still that little bit of trailing from slower than optimal pixel transitions, but you can see that the object is a bit more clearly defined (less of a broad smear) even compared to the 60Hz reference. This is particularly noticeable on the alien’s head and the legs of the UFO. In addition to the perceived blur being reduced, where the frame rate exceeds 60fps and ideally matches the 75Hz refresh rate (i.e. 75fps), there is an increased ‘connected feeling’ with the display. There is due to the delay between frames being reduced and the fact that more content (up to 1.25 times that at 60Hz) is being displayed every second. Whilst this won’t give the same experience as a 120Hz+ monitor, it does give a bit of an edge over 60Hz which some users will like.

Running a custom resolution (overclocking)

The monitor will comfortably run at up to 75Hz at 2560 x 1440 when connected by DP 1.2. By ‘comfortably’, we mean there is no change in image quality (gamma, colour balance, contrast etc.) and no frame skipping. The monitor is also left at its default timings, it’s purely the refresh rate value that is altered by the user. This is therefore ‘true 75Hz’. We also tested the monitor at 80Hz with standard timings, but frame skipping was introduced. There was little point in testing values between these, as we like to keep a bit of a buffer and the actual perceived differences between say 75Hz and 78Hz (which may not even be doable) would be negligible. Other users have reported receiving units that do not run at 75Hz without frame skipping, so there may be some inter-unit variation going on.

To run the monitor at 2560 x 1440 @ 75Hz you need to create a ‘custom resolution’. You don’t need to mess around with timings and suchlike, so the process is rather straightforward. The following video runs through how to create a custom resolution to ‘overclock’ the monitor using either the Nvidia Control Panel, or for AMD users in particular, a tool called CRU (Custom Resolution Utility).

This is what we consider a ‘mild’ overclock for a monitor, a slight bump in refresh rate that the monitor handles very comfortably. With this, there is minimal risk involved and it’s fair to assume that the monitor will last for its useful lifetime much as it would running at its native 60Hz refresh rate. Even so, as with any form of overclocking you’re doing this at your own risk. The risk may well be very low, but we accept no liability should anything happen to the monitor which may or may not be due to running it at an increased refresh rate. For the sake of this review, including the section that follows, the monitor was run at 60Hz as normal.

Responsiveness in games and movies

On BF4 there was a moderate degree of blur. This was predominantly caused by eye movement and in-line with what you’d see on even the fastest 60Hz LCDs. There was some trailing from slower than optimal pixel transitions here and there. This was most pronounced where there were dark objects set against a medium background – for example gunmetal greys from gun turrets on vehicles or aircraft moving against a rich blue sky. You could see a reasonably faint trail on top of the perceived blur from eye movement. This was not particularly widespread and not something most users would likely notice. There was no observable overshoot, which is good.

On Dirt Rally things were again much as you’d see on even the fastest 60Hz LCDs, with eye movement and perceived blur being the predominant factor. There were some slower than optimal pixel transitions, most notably between dark and somewhat lighter (‘medium’) shades. Dark shaded vegetation against lighter sandy soils, for example, had a little bit of an extra blurry appearance to them as you raced past them. This was quite subtle really, and likely something most users would fail to notice or care about – not really something that catches the eye when passively observing. There was no obvious extended trailing as you get on some slower models nor any observable overshoot, so overall a decent balance to the pixel overdrive.

We also tested our Blu-ray movie test titles, and here there were no particular issues caused by the monitor’s pixel responsiveness. There was no observable overshoot nor any trailing from sluggish pixel responses. The frame rate at which these films run (~24fps) is the main factor limiting the fluidity – the monitor didn’t impose any additional limitations on top of that.

The 2560 x 1440 (WQHD) experience on a 23.8” screen

The typical size for a monitor with the 2560 x 1440 (WQHD) resolution is 27”, giving a pixel density of 108.79 PPI (Pixels Per Inch). We’ve also tested a 25” WQHD screen and commented on how the slightly tighter (8% higher) pixel density of 117.49 PPI changes things just a little bit. With its 23.8” screen and WQHD resolution, the Dell P2416D further increases the pixel density to 123.41 PPI (13.4% higher than the 27” WQHD models). Rather than give you a visual comparison of the differences between this 23.8” WQHD screen and a 27” WQHD screen, we’ve gone for a slightly different and perhaps more striking comparison. The following images show the Dell alongside a screen of similar size but with a 1920 x 1080 (Full HD) resolution (namely the 23.6” Samsung S24E390HL). The Samsung has a pixel density of 93.34 PPI – the pixel density of the Dell is over 32% higher than this. The image below is a ‘mashup’ to compare the two monitors displaying the desktop in their respective native resolution, without any scaling employed. Here the Dell is referred to as the ’16D’ for short.

You can see that desktop elements such as various icons, the clock, start button and the wonderful Cortana search box are significantly smaller on the Dell. When comparing to a 27” WQHD model the difference is obviously not as stark – there certainly is a noticeable difference, though. Unfortunately we don’t have images comparing the two due to our camera dying on us when we were testing such a model, but just bear that 13.4% difference in pixel density in mind. Icons and other desktop elements on a 27” WQHD model are therefore some way between the two monitors shown above, but a bit closer to the WQHD Dell than the Full HD Samsung. Going back to the comparison with a Full HD screen of similar size, the images below give you an idea of how much ‘real-estate’ (useful work space) you get on the P2416D. The top image shows our website running on this monitor (left) and Samsung S24E390HL (right). You can see that you get a lot more content on the screen at once. The second image shows the multi-tasking potential that this gives you on the Dell, with a Microsoft Word document and Microsoft Excel Spreadsheet opened side by side.

Despite the pixel density being rather tight on the Dell, we didn’t have to use any scaling and found text and other elements perfectly readable from our normal viewing distance (around 70cm), but some users may prefer to use scaling. If you do, just be aware of the potential pitfalls which are touched upon in our article on the ‘4K’ UHD experience. When it comes to gaming; compared to a similar sized model with Full HD resolution (S24E390HL), the difference in detail and clarity is rather profound. Textures look sharper and more detailed, maintaining a good clarity well into the distance that is lacking at 1920 x 1080. Linked to this is the fact that the need for anti-aliasing (AA) is reduced – not eliminated by any means, but things certainly look better with lower levels of AA than at Full HD. In short; things just look better.

But this can also be said to a large extent when comparing a 27” WQHD model to a ~24” Full HD model. So a more interesting comparison is with a 27” WQHD model as well as 32” or smaller ‘4K’ UHD models with a 3840 x 2160 resolution. As we explored in the ‘2560 x 1440 (WQHD) experience’ section of this review, having the WQHD resolution applied to a 25” screen gives you a bit of a bump up in clarity and detail compared to 27” WQHD – but nothing dramatic. The 23.8” WQHD screen of the Dell provides yet another boost in this area. Things still don’t look like they do on a ‘4K’ UHD (3840 x 2160) screen that is 32” or smaller, but that’s perhaps not surprising given that you’re comparing a pixel density of 123.41 PPI to one of <137.68. The experience is really a nice ‘happy medium’ between these UHD models and a 27” WQHD screen.

The relative strengths are particularly easy to assess on good textures, such as many featured on the Star Wars Battlefront beta. These textures simply look extremely crisp and detailed when viewed on a 32” or smaller UHD screen, whereas on a 27” WQHD screen they look less so but still decent. On this 23.8” WQHD screen they look quite impressive really – some way between the two. Where low levels of anti-aliasing are used or it’s entirely absent, the ‘shimmering look’ and jagged edges in places are again somewhat less pronounced than on a 27” WQHD screen but more so than these pixel-dense UHD screens. Of course this extra detail and clarity you get at 23.8” compared to 27” at 2560 x 1440 is essentially a bonus you’re getting ‘for free’, because the resolution and hence power requirements for the system remain the same. This is undoubtedly an interesting alternative for those looking for a crisp and detailed experience in their games without needing the horsepower to push 3840 x 2160 pixels. Although it by no means represents what you’d actually see first-hand on the monitor, we’ve included a couple of images below of the monitor running various games.

Interpolation and upscaling

As with any LCD monitor, the screen has pixels of fixed dimensions. It is designed to run at its native resolution, which in this case is 2560 x 1440 – corresponding to the number of pixels on the screen. Users may wish to connect an external device such as a games console to the monitor or may not have the graphical horsepower to run at 2560 x 1440 in certain games. You can instead run the monitor in 1920 x 1080 by allowing the monitor to use interpolation to display this lower than native resolution. Doing this on a monitor almost always results in a certain loss of sharpness compared to a screen on similar size running 1920 x 1080 natively. To gain optimal results and make sure the monitor rather than GPU is handling the necessary interpolation process it is necessary to configure the graphics driver (if using a PC) to allow the monitor to handle the scaling rather than the GPU.

AMD users needn’t do anything in particular, as the factory defaults for the Catalyst Control Centre will allow the monitor rather than GPU to handle the interpolation. To double check things are correct, open Catalyst Control Centre and navigate to ‘My Digital Flat-Panels – Properties (Digital Flat-Panel)’. Ensure ‘Enable GPU up-scaling’ is unchecked (not ticked) and hit apply if this box was originally checked and you have unchecked it. Things should be setup in a similar way to the below image on modern AMD drivers.

Nvidia users should open Nvidia Control Panel and navigate to ‘Display – Adjust desktop size and position’. Ensure ‘No scaling’ is selected and ‘Perform scaling on:’ is set to ‘Display’. This is shown in the image below.

When gaming and allowing the monitor to handle the scaling in this way, things were significantly sharper than we’ve seen on some WQHD monitors using interpolation. There was a bit of softening compared to running Full HD natively on a similarly sized screen but it was quite useable and actually rather good as far as interpolation processes go. When gaming you lost a little clarity in the distance and a bit of texture detail, but things did not look like a ‘soft focus’ lens was being used – a far cry from where the GPU handles the scaling or when using a monitor with poorer interpolation handling. If you keep the monitor at 2560 x 1440 but are viewing 1920 x 1080 content such as movies, the softening is much less pronounced. Rather than the monitor using interpolation or doing anything different at all, the GPU or movie software upscales the image. When compared to viewing such content on a native 1920 x 1080 screen there is a minor degree of sharpness lost, but this is rather subtle really.

Conclusion

The Dell P2416D is one of the most aggressively priced WQHD (2560 x 1440) models out there. But don’t let that low price fool you, there is still a lot to like about this monitor. The pixel density of 123.41 PPI provides a nice medium between the usual 27” WQHD models and similar sized or somewhat larger (~32”) UHD (3840 x 2160) models. This provides strong clarity and detail whilst gaming without the same GPU horsepower requirements as ‘4K’. Despite a few (possibly inconsequential) corners being cut, such as the presence of 6-bit + FRC dithering in place of the usual ‘true 8-bit’ colour reproduction, the overall image quality is much like on this model’s larger and more expensive counterparts. A generous sRGB colour gamut, light matte screen surface and strong colour consistency help provide a rich and varied image with accurate shade representation.

From a contrast perspective there were no nasty surprises, with the static contrast largely as specified and a decent performance in that respect overall. The usual ‘AHVA glow’ that is commonly associated with IPS-type panels did eat away at some peripheral detail, but overall distinctions between even closely matching shades were good. The gamma tracking was also excellent in all but one mode – ‘Custom Color’ – where colour channels can be manually adjusted. Fortunately our unit could go without manual tweaks to the colour channels, but it would have been nice to have this strong gamma performance maintained in the ‘Custom Color’ image mode as well. Especially as there are no guarantees when it comes to colour balance in various image modes.

When it came to pixel responsiveness things were also quite as we’ve seen from some recent IPS-type models we’ve tested. The 60Hz refresh rate is really the main barrier when it comes to perceived blur on this monitor, with just a bit of additional trailing in places from slower than optimal pixel responses. Input lag is quite often a problem for sensitive users on WQHD models, with weaker performance in that respect than most Full HD models. This wasn’t an issue with this model at all – with a surprisingly low level indicating a negligible signal delay. Overall this monitor is certainly a compelling package, well worth considering if you’re after an affordable WQHD model that’s a pleasure to use for both work and play.

 

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