AOC U3277PWQU

Responsiveness

Input lag

Input lag was assessed for the U3277PWQU using a sensitive camera and a tool called SMTT 2.0. The monitor was compared to various screens of known latency, with over 30 repeat readings taken to help maximise accuracy. Using this method, we calculated 33.65ms (over 2 frames) of input lag. This value reflects not only the signal delay (element you ‘feel’) but also an element of pixel responsiveness (element you ‘see’). This indicates a moderately high signal delay, which some users might find troublesome but others won’t mind.

Perceived blur (pursuit photography)

In this article we look at the factors affecting the responsiveness of a monitor. One of the key concepts explored here is ‘perceived blur’, contributed to both by the pixel responsiveness of the monitor but more significantly the movement of our own eyes as we track motion on the screen. We also introduce the idea of ‘pursuit photography’, which is a method used to capture motion on a monitor in a way that more closely reflects what the eye sees. This is done by using a moving rather than stationary camera, so the end result reflects not only the pixel responses of the monitor but also the movement of our eyes (camera) as motion is tracked.

The images below show pursuit photographs taken using the UFO Motion Test for ghosting, with the test running at its default speed of 960 pixels per second. This is a practical speed for such photographs and sufficient to allow the key components of perceived blur to be analysed. The monitor was set to various ‘Overdrive’ settings; ‘Off, ‘Weak’, ‘Medium’ and ‘Strong. The middle row of the test (medium cyan background) was used primarily, with one additional photograph taken with a white background. This photograph was taken only with ‘Overdrive’ set to ‘Off’ rather than repeated for every setting. This is simply because this transition was not affected by the ‘Overdrive’ setting and appeared the same regardless. The final image shows a fast 60Hz reference, namely a Samsung S27A750D set to full brightness (avoids PWM) and its optimal response time setting. This shows how things should look on a 60Hz LCD where it is only the movement of the eyes that is contributing to perceived blur, not pixel responsiveness.

Perceived blur with various settings

With ‘Overdrive’ set to ‘Off’, you can see a bold but very short ‘trail’ of sorts both behind and in front of the object. Note that the object runs across the screen from left to right. This indicates some weakness in the transition between the object colour (red) and background colour (cyan) and also some weakness between the background and object. It almost looks as if the object is highlighted with a marker pen, but curiously you don’t get the sort of extended trailing behind the object that you’d usually see on a VA panel for such transitions. This trailing becomes extended during faster motion speeds, but that is very challenging to capture in a pursuit photograph due to the camera movement speed and stability required. What is also interesting is that results with the dark cyan background, which usually show even more pronounced trailing on VA panels, were very similar to the medium cyan backgrounds Hence they weren’t included in this comparison. Pixel transitions were noticeably slower where a very light (white, in this case) background was used as per the second image. Here you can see more extensive trailing behind the red UFO body, although it’s still reasonably faint in this instance.

The ‘Overdrive’ setting did not affect the transitions where a white background was used, hence why it was only shown for ‘Off’. The medium cyan background did show some differences, however. Using the ‘Weak’ setting introduced a bit of overshoot (inverse ghosting) which is visible as a dirty trail behind the UFO body and an inverted ‘halo’ trail behind the red body. The bold marker-pen type outline remained to a large extent, however. Using the ‘Medium’ reduced this outline, especially behind the object, but introduced more noticeable and colourful inverse ghosting. The ‘strong’ setting ramped this up considerably, providing very obvious and very eye-catching inverse ghosting. What is interesting in this analysis is the ‘Off’ setting seems optimal, either because the panel is natively as fast as it needs to be or that it already provides a decent level of acceleration (‘Off’ does not always mean that no grey to grey acceleration is used on some level). Even the ‘Weak’ setting introduces some noticeable inverse ghosting in practice and any higher (‘Medium’ etc.) provides very obvious inverse ghosting that is rather unsightly. As far as this test goes, the monitor has really done surprisingly well for a VA panel – but it’s important to consider a broader range of pixel transitions both in terms of shades used and speeds of transition. For this, ‘real-world’ analysis using a range of game titles works nicely.

Responsiveness in games and movies

On Battlefield 4 (BF4) there was a fair degree of blur, contributed to predominantly but not entirely by eye movement. In addition to this perceived blur due to eye movement, some weaknesses in pixel responses were evident. The monitor was actually quite unusual in its pixel response performance, for a VA panel. Rather than some transitions being noticeably fast and some noticeably slow, the vast majority of transitions were reasonably fast. There was a bit of weakness that was quite widespread, giving a bit of extra blur in most cases. This became more noticeable at faster transition speeds, for example when turning the character quickly or zipping around in a nimble vehicle such as a Jeep. There was by no means an extreme degree of additional blur, but was just an additional ‘layer of blur’ to contend with.

Although ‘high contrast transitions’ were actually somewhat faster than on most VA models, there were some weaknesses here similar to what was shown earlier with the UFO Motion Test analysis. Where there were dark objects (such as a dark-painted vehicle) against a lighter background (such as bright sky) there was a slightly extended trail. This was again not ‘smoke-like’ as it would appear on some VA models, but it did stand out compared to the other transitions which were faster. The dark object also appeared to break up slightly so that very dark red or purple could be seen (this is something we’ve seen on VA panels before, that we refer to as ‘fringe-like trailing’). Likewise, where bright objects (such as white uncapped objective markers) moved against a darker background, there was a bit of extended trailing going on. No inverse ghosting (overshoot) could be observed, which is good.

We made similar observations on Dirt Rally. Most perceived blur was linked to eye movement and in-line with what you’d see on even the fastest 60Hz LCDs. There was a widespread ‘mask’ of additional blur on top of this, which was reasonably subtle for the most part and didn’t really affect the gameplay. Sensitivity to this sort of thing varies and it’s fair to say it is significant enough to give sensitive users slightly more of a dizzying sensation during gameplay than they might otherwise get. Having said that, it’s more than likely that any users with serious motion sickness issues would find the experience of any 60Hz LCD to be problematic. There were again some examples of slower ‘extended’ trailing, quite common where dark and shaded trees and vegetation were cast against a backdrop of bright sky. Whilst racing at night this more noticeable extended trailing became more of an issue, too. But as noted on BF4, it wasn’t the sort of extended ‘smeary’ trailing traditionally associated with VA panels. No overshoot was observed, which is good.

It’s fair to say that most of the faster transitions on this monitor are a bit slower but some of the slowest transitions similar in speed to some of the best all-round VA performers. The best performers being the likes of the Samsung S34E790C and Samsung C27F591FD, for example. So whilst this model does have some weaknesses in pixel responsiveness, it really isn’t bad as far as VA models goes and is actually one of the better models out there in that respect. We also viewed our Blu-ray movie test titles on this monitor and observed no weaknesses that wouldn’t be apparent on even the best 60Hz performers. The transition speed was perfectly adequate for movie performance on the ~24fps titles that we ran – with the frame rate itself being the main limit to fluidity.

The ‘4K’ UHD experience

In our article on the UHD experience, we look at the benefits and drawbacks of running the ‘4K’ UHD resolution of 3840 x 2160 on a 28” screen. We have also explored the experience of running this resolution on a 31.5” screen in our review of the BenQ BL3201PT/PH. Rather than repeating what we’ve already said near the end of that review, in the ‘The ‘4K’ UHD experience’ section, we would urge you to refer to that passage. The 32” screen size at 3840 x 2160 provides a practically identical experience to this 31.5” 3840 x 2160 screen. To reiterate some key points, we find the pixel density of 139.87 PPI (Pixels Per Inch) to be something of a sweet spot. By this we mean that it’s perfectly comfortable on the desktop, to our eyes, without using scaling. Although this depends on preferred viewing distance and eyesight. We feel that most users should find this usable without scaling with eyes a distance of 60 – 80cm from the screen. Some may find that buttons and UI elements are small but usable, but that text may be a bit tricky to read. So rather than having to scale everything up in the Operating System, which can bring about problems as highlighted in our ‘experience article’, they might prefer to simply use the zoom control on a per-application basis. The images below show the desktop and some of the real-estate afforded by the screen running its full native resolution without scaling.

As noted in the BenQ review linked to in the previous paragraph, this excellent pixel density works really nicely for gaming. And indeed the sheer screen size makes for a very immersive experience and allows these details to be appreciated on quite a fine level. Generally, games will not have textures or particle effects which universally take full advantage of the resolution (that would be graphically very taxing), but there are usually some stand-out textures that look really appealing. More so than on models with lower but still decent pixel densities, such as 27” 2560 x 1440 (WQHD), 34” 3440 x 1440 and 40” 3840 x 2160 (‘4K’ UHD) models. The need for anti-aliasing is also greatly reduced, and the clarity as you view distant objects on games is really very impressive. Although it gives very little idea of how the screen actually looks first-hand, we’ve included some shots from various games running in the UHD resolution.

Interpolation and upscaling

You might be looking to run the monitor at a lower resolution, for example 1920 x 1080 (Full HD), either to make a game much less demanding graphically or because you are forced to do so when using a games console. It’s a common misconception that because 1920 x 1080 divides evenly into 3840 x 2160, the monitor should just use 1:4 pixel mapping and display Full HD perfectly. In reality that doesn’t tend to happen and instead an interpolation (scaling) process is used. Exactly the same process that is applied when any other resolution is displayed, regardless of how neatly it should divide into the native 3840 x 2160. For the best results here you should make sure the monitor is handling this scaling rather than the GPU. Users of Nvidia GPUs should open 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. AMD users needn’t adjust anything as things should be set up correctly by default.

The interpolation process on the U3277PWQU provides a moderate but not extreme amount of softening. This means that you do lose a degree of sharpness compared to running 1920 x 1080 natively on a 31.5” screen. Things don’t look as soft as they do on some monitors that use interpolation, but you can certainly see a loss of definition, particularly for thin objects or the edges of objects and finer texture details. As the resolution is increased, the softening becomes somewhat less noticeable but is still there compared to running the resolution natively on a screen of similar size. 2560 x 1440, for example, looks quite decent – although again a bit softer than it should. We didn’t find ‘ClearVision’ (sharpness enhancement function using the ‘left arrow’ OSD button) helped and actually made things look quite artificial. As usual, if you keep the monitor at 3840 x 2160 and view 1920 x 1080 (Full HD) content, for example, the GPU or software ‘upscales’ rather than the monitor itself doing anything special. As usual there is a little bit of softening compared to native Full HD but it’s not dramatic.

Conclusion

With its 31.5” screen size, the AOC U3277PWQ provides something of a sweet spot for the 3840 x 2160 ‘4K’ UHD resolution. The pixel density is sufficiently high so that things look ‘distinctly 4K’, whilst not so high that things become completely unreadable without scaling. We were quite happy to use this monitor without any scaling, whilst others found using per-application zoom controls rather than having to rely on universal scaling worked nicely for them. The use of a VA panel helped compliment this experience, with strong contrast that helped bring out extra definition and maintain a superior atmosphere in dark scenes compared to competing models with other panel types. The contrast we recorded did fall slightly short of the claimed ‘3000:1’, at ~2500:1 or ~2200:1 following the adjustments made to our ‘Test Settings’.

And speaking of these adjustments, they were fairly extensive as the factory default white point was completely out of whack. Gamma tracking was quite good (although not perfect), but perhaps of more important note was the colour gamut of this monitor. Something that will prove quite divisive, we’re sure. It is a wide gamut model that doesn’t offer reliable emulation of the Adobe RGB colour space, as it falls short in some regions and over-extends in others. There is then the sRGB emulation mode, which cuts down this gamut massively. But it’s complete overkill; dropping sRGB coverage to around 85%, which is poor for a modern monitor. There was also a seemingly useless ‘Uniformity’ setting (Uniformity Compensation or UC mode), which actually made little difference to uniformity. Perhaps making it worse rather than better, in some respects. Rather than a non-functional UC mode and a useless sRGB emulation mode, we would much prefer to have seen something functional and useful like a Low Blue Light (LBL) setting. But I digress.

Another aspect we weren’t too keen on was the screen surface of the monitor, which was frankly a disappointment given how beautifully smooth and essentially ‘grain-free’ the 32” IPS-type counterparts to this model are. Whilst far from the ‘grainiest’ screen surface we’ve seen, it’s really a shame to see the same screen surface used here as on the 28” TN UHD models. It was at least what we’d classify as ‘relatively light matte’ and only gave a sort of mist of grain rather than obvious smears to the image. But it’s certainly nice to have models of this pixel density not marred at all by any noticeably grain to the screen surface. Whilst a lighter screen surface could have been preferable in terms of vibrancy preservation as well, that really isn’t something this model needed any help with. Colours were very vivid, highly saturated and ‘in your face’ – impressive in some respects, but certainly not accurate.

The only let-up in this vibrancy actually came further down or towards the edges of the screen, where a bit of saturation was lost due to the viewing angle weaknesses (perceived gamma shifts) as expected for a VA panel. The extent of these saturation and gamma changes were actually more pronounced than we’ve seen on modern VA panels from other manufacturers (AUO AMVA+ and Samsung curved SVA) – and not just due to the sheer size of the screen. The loss of detail (‘black crush’) in the centre of the screen was also more pronounced than it could have been. We still maintain that the overall atmosphere and contrast performance was strong for such scenes, but things could have been better on a finer level.

The final area of image quality to consider is responsiveness, which again left us with mixed feelings. On one hand the input is moderately high and there are some quite widespread weaknesses in pixel responsiveness which give a slight bit of extra blur for many transitions. There are also some (high-contrast) transitions which give more extended trailing. On the other hand, the overall pixel responsiveness was firmly in the ‘decent’ camp and when compared to many VA models was actually rather good. We also liked the overall package delivered here – that is to say the combination of styling (we like brushed metal) and ergonomic flexibility. The stand certainly isn’t the most solidly-built we’ve come across on this sort of monitor, but it certainly does the job. All things considered, this monitor does have its attractions but also has its drawbacks. As with all models, really, it’s about weighing these up against your own personal needs and desires.

The bottom line; a screen of two halves with some appealing strengths such as strong contrast and potentially deal-breaking weaknesses such as an untameable wide colour gamut.

 

Donations are also greatly appreciated.