AOC U2477PWQ

Responsiveness

Input lag

A sensitive camera and a small tool called SMTT 2.0 was used to measure input lag for the U2477PWQ. The monitor was compared to various monitors of known latency. Using this method, we calculated 4.85ms (between 1/4 and 1/3 of a frame) of input lag. This value is influenced both by the signal delay (element you ‘feel’) and pixel responsiveness (element you ‘see’). It indicates a very low signal delay for the monitor which shouldn’t cause issues even for sensitive users.

Perceived blur (pursuit photography)

In this article we explore the factors which affect the responsiveness of a monitor. One of these key concepts is the idea of ‘perceived blur’ and the use of a technique called ‘pursuit photography’ to capture movement in a way that reflects this. Such photography makes use of a moving rather than stationary camera to reflect not only what the screen itself is doing (pixel responses) but also the blur induced due to eye (camera) movement. It is this eye movement that is the chief contributor to the blur perceived on a modern sample and hold display.

The images below are pursuit photographs taken using the UFO Motion Test for ghosting. The test is running at 960 pixels per second with object moving from left to right – a practical speed for such photographs that highlights the key factors nicely. The monitor was set to its four different response time settings; ‘Off, ‘Weak’, ‘Medium’ and ‘Strong’, respectively. The middle row of the test (medium cyan) was used for this analysis. A 60Hz reference has also been included for comparison, which is a Samsung S27A750D set to full brightness (ensures DC backlight control) and using its optimal ‘Faster’ response time setting. This essentially shows what things should look like on a 60Hz sample and hold LCD where pixel responsiveness isn’t a limiting factor.

Perceived blur with various settings

With ‘Overdrive’ set to ‘Off’ there is a moderate amount of blur (similar to the reference) with additional trailing behind the object from slower than optimal pixel transitions. The ‘Weak’ setting reduces this additional trailing slightly, but there is still a reasonable amount remaining behind the object. The ‘Medium’ setting reduces this further so that there is only a very small amount of additional trailing behind the object. Although not clear in the image, there is actually a bit of a ‘shadow’ behind the object instead, which is mild overshoot (inverse ghosting) from fairly strong pixel overdrive. The ‘Strong’ setting, as the name suggest, ramps the pixel overdrive up significantly and brings with it obvious overshoot. You can see a colourful trail behind the object that is very obvious in practice.

Considering a broader range of pixel transitions, as we do in the following section, the default ‘Medium’ setting proved optimal. There was a bit of overshoot in places, as we explore, including some that is a bit more obvious than that shown here. The ‘Weak’ mode gave significantly more conventional trailing, though, as acceleration was simply too weak and in places gave little improvement over ‘Off’.

Responsiveness in games and movies

There was a moderate degree of blur on BF4. This was caused predominantly by eye movement and as you would see on even the fastest 60Hz LCDs. There was only a faint whiff of trailing on top of this from slower than optimal pixel responses – so faint that it wouldn’t be picked up by most users even in a side by side comparison. There was a bit of overshoot in places caused by strong pixel overdrive (grey to grey acceleration). If you strafed past dark posts or vehicles against a bright blue sky, for example, you could see a faint almost transparent trail. For some transitions a semi-transparent dark inverse ghosting trail could also be seen. For both forms of overshoot, though, this was quite faint and not at all eye-catching in our view. Sensitivity to such things varies, but we don’t feel the overshoot is at a disturbing level and overall it seemed that the monitors pixel responsiveness was well-tuned.

Dirt Rally provided a similar experience, with the vast majority of blur attributable to eye movement and thus inescapable on any 60Hz sample and hold monitor. There was again a small trace of additional trailing here and there, but nothing particularly noteworthy. There was also a bit of overshoot in places, again manifesting itself as faint partially transparent trails which were not obvious or eye-catching really.

We also tested our Blu-ray movie test titles and didn’t find any issues with sluggish pixel responses or overly aggressive pixel overdrive. The ~24fps at which the films run was the main limit to their fluidity, with the monitor displaying these as any responsive 60Hz LCD would.

The ‘4K’ UHD experience

Our ‘UHD Experience’ article discusses the ins and outs of the 3840 x 2160 (‘4K’ UHD) resolution. Although this article focused on a 28” screen, a lot of this applies equally to 23.6” screens such as this one. We’ve actually looked specifically at the UHD experience on a screen of this sort of size in the relevant section of our review of the Dell P2415Q, which is a 23.8” monitor and therefore extremely similar to the 23.6” AOC in terms of pixel density. With its 186.69 PPI (Pixels Per Inch), we found 150% scaling in Windows provided a good balance between readability and real-estate. If you run the monitor at its native 100% setting (no scaling) then text and UI elements are tiny. Whilst still technically usable, if sitting quite close to the screen, we think most users would find this rather uncomfortable and quite odd really and would therefore prefer to use scaling. The photos below show the desktop without scaling (top photo) and with our preferred 150% setting (bottom photo). Note the differences in icon size.

As explored in the P2415Q review, the 150% scaling setting still leaves you with a good amount of real-estate on the screen for general desktop use. And as we explore here, applications with independent zoom control (such as web browsers, office applications and many others) will still allow you to use this independently of any scaling. The image below shows the sort of space you get to play with for multi-tasking and also shows how different applications might handle this 150% scaling. On the left side of the screen you can see the store open in the EA Origin client, which currently ignores scaling entirely and displays everything in the tiny native ‘no scaling’ state. On the right side of the screen you can see our homepage using the default zoom level of the browser for 150% scaling, but this can be independently adjusted as noted previously.

As explored in the Dell review and the article linked to above, the excellent pixel density brings about a significant boost to the clarity and potential detail levels when gaming. We will again reiterate that a 23.6” screen doesn’t really look significantly ‘better’ than a UHD screen up to around 32”, even though the pixel density is a fair bit higher. It’s also important to note that some games certainly make better use of the resolution than others. We would like to bolster our assessment of the UHD gaming experience by discussing a new title that we got our hands on; Tom Clancy’s The Division. This is a very appealing game, visually, that makes excellent use of the UHD resolution. Even with graphics settings set rather low, the overall clarity afforded by the pixel density is excellent. This makes objects in the distance appear very sharp and relatively detailed. Even with the basic AA filtering in the ‘Low’ preset, such objects were free from distracting jagged edges. If you up the graphics details then things start to look very impressive indeed. The clarity of objects into the distance is exceptional, whilst the texture details of many objects even close up was very impressive indeed.

As we’d seen on other titles there were some textures that looked a little flat if you were quite close to them. But no texture on this game looked so poor as to look out of place, it’s just that some made better use of the pixel density than others. The clothes of characters have very detailed material textures, with an appropriate fluffy look or specular lustre depending on the material used. All of the minute creases (and micro-creases, if there’s even such a term) help provide a sense of realism to these materials that simply isn’t there at significantly lower pixel densities. One of the most impressive textures, at least on the area of the game we tested, was the ‘grippy’ metal surface towards the bottom of the police van shown in the top image below. This had a beautiful 3D structure to it and was complimented by very realistic lighting and shadow detail. The images below are simply for illustrative purposes and in no way reflect what things actually look like first-hand on the monitor.

Interpolation and upscaling

If you find the native 3840 x 2160 (‘4K’ UHD) resolution too demanding for certain applications, it may be tempting to reduce the resolution to something less demanding like 2560 x 1440 (WQHD) or 1920 x 1080 (Full HD). Alternatively, you may wish to connect a device such as a games console that will only run at a lower resolution such as 1920 x 1080. If you do this, an interpolation (scaling) process will be used to display this native resolution. It is best to let the monitor handle this rather than the GPU of the PC. AMD GPU users needn’t worry as the default settings dictate that the monitor rather than GPU will automatically handle the interpolation when gaming. Nvidia GPU users should open their Nvidia Control Panel and navigate to ‘Display – Adjust desktop size and position’. They should then ensure that ‘No Scaling’ is selected and ‘Perform scaling on:’ is set to ‘Display’ as illustrated below.

Many people mistakenly believe that 1920 x 1080 will be displayed ‘perfectly’ on a 3840 x 2160 display without any loss of clarity compared to a native Full HD display using 1:4 pixel mapping. That isn’t generally the case in practice, though, and usually the same sort of interpolation process is used whether you’re trying to display 1920 x 1080 or a different non-native resolution. The AOC actually retains a respectable degree of sharpness when using interpolation to display 1920 x 1080 – there is a degree of softening, but not as much as we’ve seen on some other UHD displays. If you set ‘ClearVision’ to ‘Weak’ (the second OSD button activates this, as per the video) then it actually counteracts some of this softness as well and brings things fairly close to a native Full HD display of similar size. Any higher ‘ClearVision’ setting will provide an overly sharp image. 2560 x 1440 (WQHD) is also displayed well, but only if ClearVision is disabled – otherwise things look overly sharp. There is again a degree of softening, but it’s not extreme. Essentially the monitor uses one of the best interpolation processes we’ve come across on a UHD model, so it’s very usable in non-native resolutions.

If you’re running lower resolution content (such as a Full HD Blu-ray) using software on the PC, but keep the monitor at its native 3840 x 2160, it is the GPU or software that handles the scaling. The monitor does not influence this process. There is a bit of softening but nothing extreme. Given how well the monitor handles interpolation some users may actually find it better to set the monitor itself to Full HD for a slight edge in sharpness for Full HD content compared to 3840 x 2160.

Conclusion

The AOC U2477PWQ strikes a pleasing balance between price, design, practicality and image performance. Despite being one of the lowest priced UHD models on the market, it provides a competent performance in many areas. Its PLS panel was well-tuned to provide rich, accurately represented and consistent colours. Gamma handling was strong straight from the box and with a few tweaks elsewhere the colour reproduction was pleasing. The light matte screen surface and fairly generous (but still not ‘wide’) colour gamut also aided the monitor in this respect. The resolution does in itself also provide definite benefits – exceptional clarity, real-estate and detail in a range of applications. On a 23.6” screen, though, scaling will be something of a necessity for most users for general desktop use – and not all applications handle this particularly well, if at all.

The contrast performance was largely as you’d expect given the panel type – actually slightly better, as the level of ‘PLS glow’ was a bit lower than you’d typically see. This allowed the monitor to retain somewhat more detail towards the peripheral regions of the screen –nonetheless, there was still some noticeable glow. The screen surface is ‘light matte’ as mentioned previously, bringing out a decent level of vibrancy and clarity. The surface texture did impart a light and misty graininess, though, so white and other light colours weren’t as smooth as we’ve seen on some models. There wasn’t the same course or smeary grain seen on some matte surfaces, fortunately. It’s also worth mentioning that a ‘Uniformity’ setting (uniformity compensation mode) also featured, which did what it said on the tin. There was a slight hit in contrast and locked and fairly high brightness settings when using this, however.

Responsiveness was also quite pleasing, overall. There were a few imperfections in terms of some slightly slower than optimal pixel transitions as well as a bit of light overshoot here and there. Overall, though, the pixel responsiveness was quite well-tuned and generally things looked quite in-line with event the fastest 60Hz LCDs. We were also pleased to see that the monitor handled interpolation well – as well as we’ve seen from a UHD model, in fact. This makes the monitor suitable for secondary usage on games consoles or for more demanding games where a lower resolution is preferred for performance reasons. Given the asking price there really is a lot to like about this model – and its flexibility to display non-native resolutions rather well makes it even more approachable.

The bottom line; a monitor that hits the sweet spot between price and performance whilst looking and feeling like quite a premium product.

 

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