AOC Q2577PWQ

Responsiveness

Input lag

We used a piece of software called SMTT 2.0 alongside a sensitive camera to compare the latency of the Q2577PWQ with a range of monitors of known input lag. We took over 30 repeat readings using this method to measure 18.68ms (just over 1 frame) of input lag. This is influenced both by the element you see (pixel responsiveness) and that which you feel (signal delay). This indicates that the monitor has a moderate signal delay that will bother some users sensitive to input lag but not others. You shouldn’t worry about this unless you specifically know you are particularly sensitive to input lag.

Perceived blur (pursuit photography)

Our responsiveness article explores some important concepts related to the responsiveness of a monitor. It is important to realise that it isn’t just pixel responsiveness that dictates how much motion blur you see on a monitor. In fact the movement of your own eyes as you track motion is the most significant contributor to perceived blur on modern monitors. By using a method of photography known as ‘pursuit photography’, you can accurately capture motion on a monitor in a way that indicates what your eye sees when tracking motion. A moving camera is used to capture images, showing not just ‘trailing’ from sub-optimal pixel responses but also highlighting blur that is caused by eye (in this case camera) movement. Additional imperfections such as inverse ghosting (overshoot or Response Time Compensation errors) are also highlighted.

The following images are pursuit photographs taken using the UFO Motion Test for ghosting, with the test running at 960 pixels per second. This rate is practical for such photographs and highlights the pixel response elements and eye (camera) movement elements of motion blur. The ‘medium cyan’ background (middle row) of the test is used with the monitor set to various ‘Overdrive’ settings; ‘Off’, ‘Weak’, ‘Medium’ and ‘Strong’. The final picture shows a 60Hz reference monitor, a Samsung S27A750D set to full brightness (this eliminates PWM) and 60Hz, using its ‘Faster’ response time setting. This reference shows motion blur that would be caused almost entirely by eye movement if you were observing movement on the monitor, without pixel responsiveness being a limiting factor.

Perceived blur with various settings

With ‘Overdrive = Off’, you can see a significant amount of trailing beyond what is seen on the reference screen. This indicates weaknesses in pixel responsiveness, influencing perceived blur. The ‘Weak’ setting decreases this somewhat, particularly behind the UFO itself. A significant improvement can be had by using the ‘Medium’ setting, which is actually the factory default. For the transitions analysed here there is only a little bit of trailing from slower than optimal pixel responses – it doesn’t look a million miles from the reference screen really. The ‘Strong’ setting introduces a moderate amount of overshoot (inverse ghosting), which can be seen in the image as an inverted bright trail behind the object.

From this analysis it is clear that the ‘Medium’ setting is optimal. In our game testing that follows we consider a broader range of pixel transitions and indeed it is readily apparent in this testing the ‘Medium’ is the best setting to use. Overshoot using the ‘Strong’ setting is readily apparent and fairly off-putting, without any obvious benefit elsewhere. The ‘Weak’ setting meanwhile gives a fair degree of additional trailing from sluggish pixel response times compared to the ‘Weak’ setting. We will not be including a section on ‘overclocking’ in this review as we were only able to set the monitor as high as 65Hz comfortably, without significant frame skipping or other negative consequences. This was the case regardless of connection used, and we don’t feel setting the monitor to 65Hz provides any palpable benefit over 60Hz anyway.

Responsiveness in games and movies

Whether stalking your prey on foot or zipping around in a nimble vehicle on BF4, the perceived blur was very much as you’d see on even the fastest 60Hz monitors. There was really very little weakness in the way of pixel responsiveness, with just the slightest (and fairly rare) whiff of trailing on top of what is observed due to eye movement alone. There was no noticeable overshoot, either, with just the lightest trace during a small minority of transitions. These involved light and medium-light shades moving against each other, for example when strafing past light metal posts with snow in the background. The overshoot was very difficult to spot and actually blending in quite well anyway, it’s not something even those with trained eyes will have an easy time spotting. It is clear that AOC have done an excellent job of fine-tuning the pixel overdrive in the default ‘Medium’ setting. This is really about as good as it gets with respect to perceived blur on a 60Hz LCD and one of the best performances we’ve seen from a 60Hz WQHD model.

Dirt 3 told a similar story – one of pixel responses doing little to hold things back. Whether cruising along rally tracks or spinning around like a lunatic on Gymkhana, there was a moderate to strong degree of blur that was caused almost exclusively by eye movement. There was no obvious trailing on top of this nor any noticeable overshoot, with mere traces of both that are barely worth a mention. Obviously the refresh rate itself holds things back in this respect, but by now you should be well aware that you’re reading a review of a 60Hz monitor here.

We also tested our Blu-ray movie test titles, which did not highlight any weaknesses in pixel responsiveness. The fluidity was limited by the low frame rate at which the films run (~24fps), but was not impeded by pixel responsiveness; there was no trailing or overshoot related to imperfections in that department.

The 2560 x 1440 (WQHD) experience on a 25” screen

Most models with a 2560 x 1440 (WQHD) resolution have those pixels spread across a screen measuring 27” diagonally, providing a pixel density of 108.79 PPI (Pixels Per Inch). With its 25” screen, the AOC Q2577PWQ yields a slightly tighter pixel density of 117.49 PPI – roughly 8% higher. This isn’t a monumental difference, but it is a difference nonetheless. It does, amongst other things, make text and various other elements on this screen just a little bit smaller in comparison to 27” WQHD screens. The images below show the AOC beside a Philips 272P4APJKHB, a 27” WQHD model. Note that this is a wide gamut monitor and therefore looks very different, especially on camera, in terms of white point and colour balance. Ignore those differences – this demonstration is simply to give a rough idea of the different screen sizes and the relative size of text and graphical elements on the 25” vs. 27” screen.

We found the 25” screen and 2560 x 1440 resolution combination very comfortable to use for text-based work, reading websites and other such tasks. The amount of real-estate was pleasing, although obviously not as high as on 3840 x 2160 (‘4K’ UHD) models. On the plus side, we found the screen very much useable without relying on scaling, which isn’t something we can really say for UHD screens of this sort of size. The images below show the Q2577PWQ (which we will affectionately call the ‘Q25’) on its own displaying a ‘blank desktop’ and running the Microsoft Edge web browser and Microsoft Word simultaneously. This should give you an idea of the sort of ‘real-estate’ you have at your disposal on this model, without scaling and 100% zoom on each application.

When it comes to gaming, the slightly tighter pixel pitch doesn’t bring anything revolutionary to the experience over a 27” screen with the same resolution. If you consider 32” or smaller ‘4K’ UHD (3840 x 2160) screens, you get an obvious jump up in clarity and detail compared to a 27” 2560 x 1440 screen. Provided they are of sufficient resolution to start with, textures in games appear much more detailed whilst there is an obvious change to the clarity and sharpness as you stare into the distance on your game world. There are some definite ‘wow’ moments there. Comparing 25” to 27” WQHD screens, though, the differences are much more subtle. Things do look just a touch sharper in general, but really don’t look too dissimilar to on a 27” model with such a resolution and similar screen surface. This isn’t necessarily a bad thing, though, as the 2560 x 1440 resolution on both 25” and 27” screens provides a nice level of detail and clarity when gaming. It gives a significant bump up in these aspects compared to a 1920 x 1080 (Full HD), without being anywhere near as taxing as the 3840 x 2160 resolution. We will round off this section by providing some images of various games running on the monitor; obviously giving no indication of what it actually looks like in person but simply setting the scene(s).

Interpolation and upscaling

With the monitor running at its native 2560 x 1440 (WQHD) resolution, everything appears clear and sharp. You may wish to run the monitor at a lower resolution, such as 1920 x 1080. Perhaps if your GPU lacks the horsepower to play a particular game title in WQHD or if you’re connecting the monitor to another device such as a games console. When you do this, the monitor uses an interpolation process to fill its 2560 x 1440 pixels with the 1920 x 1080 image. There is no 1:1 pixel mapping feature on the monitor, so if you wish to have the lower resolution centres without any sort of interpolation used you would need to select the appropriate option in the graphics driver.

When running the monitor at 1920 x 1080, things look somewhat softer than they would on a monitor displaying 1920 x 1080 natively on a monitor of similar size. The sharpness is a lot better than we’ve seen on many monitors when using interpolation, however. Text appears a bit softer and images do not appear quite as defined as they should, but they still maintain a decent degree of sharpness. A similar experience is had whilst gaming, with textures not appearing as sharp or detailed as they should – a moderate but not excessive softening. If you are viewing 1920 x 1080 content such as movies but have the monitor resolution at its native 2560 x 1440 then the loss of sharpness is again not all that pronounced. The monitor itself doesn’t actually influence what’s going on there, it’s the GPU or software that upscales the image. As usual there is a slight softening compared to running the movie on a native 1920 x 1080 screen of similar size and screen surface, but it’s quite subtle and certainly far removed from what is seen when the monitor interpolates. You certainly can’t counteract this by using the ‘Clear Vision’ function, but you shouldn’t really feel the need to either – the monitor is a fine choice for Full HD movie watching, overall.

Conclusion

The 2560 x 1440 (WQHD) resolution is nothing new, but until relatively recently monitors which used the resolution came at a huge premium over lower resolution models. The AOC Q2577PWQ makes use of a slightly smaller panel compared to the usual for the resolution, at 25” rather than 27”. This has allowed the manufacturer to price this model very aggressively, making it one of the most affordable 2560 x 1440 models on the market. Despite its price tag and cut down screen size, image quality is just as good as on many of its larger and more expensive counterparts. The image did look extremely bright and somewhat bleached out of the box, but this was easy to rectify with some very simple tweaks of the OSD.

Once brightness was lowered and the gamma mode was changed, the image was rich, varied and appealing. The white point of our unit was right where it should be according to the 6500K daylight target right from the box, so there was no need for us to modify colour channels for our ‘Test Settings’. Gamma tracking was a bit off compared to the conventional 2.2 curve, but this didn’t detract from the experience for general usage (including games, movies, ‘work’ and browsing the internet) and if anything added a bit to it. Given the colour consistency of the AH-IPS panel, the light matte screen surface and generous (but still not ‘wide’) colour gamut, the image was pleasing in both depth and variety.

The contrast performance was very much as expected from a modern IPS panel, fairly good but with the usual ‘IPS glow’. There was also a little bit of extra detail lost due to the gamma behaviour of the monitor, but nothing substantial. Responsiveness was also pleasing overall, especially from a pixel responsiveness perspective where there were no real weaknesses for a 60Hz monitor. The input lag moderate, which may put some off but shouldn’t deter most users. All in all this was a solid monitor with pleasing performance and an even more pleasing price tag – one that’s well worth the money.

 

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