AOC CQ27G2U (CQ27G2)

Interlace pattern artifacts

On some monitors, particularly but not exclusively those with high refresh rates, interlace patterns can be seen during certain transitions. We refer to these as ‘interlace pattern artifacts’ but some users refer to them as ‘inversion artifacts’ and others as ‘scan lines’. They may appear as an interference pattern, mesh or interlaced lines which break up a given shade into a darker and lighter version of what is intended. They often catch the eye due to their dynamic nature, on models where they manifest themselves in this way. Alternatively, static interlace patterns may be seen with some shades appearing as faint horizontal or vertical bands of a slightly lighter and slightly darker version of the intended shade. We did not observe either artifact type on this monitor.

Responsiveness

Input lag

We used a small tool called SMTT 2.0 and a sensitive camera to compare the CQ27G2U (CQ27G2)’s latency with a screen of known latency. To help maximise accuracy, over 30 repeat readings were taken. Using the method and Adaptive-Sync enabled in the driver and OSD, we measured 4.98ms (over 2/3rds of a frame @144Hz) of input lag. At 60Hz we measured a slightly higher but still reasonable 7.48ms. Similar results were recorded with Adaptive-Sync disabled and ‘Low Input Lag’ enabled instead. These input lag values are influenced by the element of input lag you ‘feel’ (signal delay) and also the element you ‘see’ (pixel responsiveness). It indicates a low signal delay at 144Hz which most users should find acceptable. We don’t have the means to accurately measure input lag with Adaptive-Sync active in a variable refresh rate environment.

Perceived blur (pursuit photography)

Our article on responsiveness explores some of the key concepts related to monitor responsiveness. A key concept explored is perceived blur, something contributed to by both the pixel responsiveness of the monitor and the movement of your eyes as you track motion on the screen. Both factors are important, but the second factor is actually dominant on modern monitors. We also explore a technique called ‘pursuit photography’ which captures motion on a screen that reflects both of these factors. In contrast with regular static photos or videos, which can only reflect weaknesses in pixel responsiveness.

The images below are pursuit photographs taken using the UFO Motion Test for ghosting, with the UFO moving across the screen from left to right at a frame rate matching the refresh rate of the display. The test is set to run at its default speed of 960 pixels per second, which is a practical speed for such photographs whilst highlighting key weaknesses appropriately. The monitor was tested at 60Hz (directly below), 100Hz and 144Hz with all of the ‘Overdrive’ settings tested; ‘Off’, ‘Weak’, ‘Medium’ and ‘Strong’. 120Hz is also selectable even though it isn’t shown in the initial analysis below – it behaved some way between 100Hz and 144Hz as you might expect. All rows of the UFO Motion Test were used, highlighting a range of pixel transitions between various shades. The final columns show some reference screens for comparison, where possible, using what we deem to be their optimal pixel response time settings. The first reference screen is the AOC AG273QCX, a VA model using an older 1800R curved variant of this panel. The second reference is the ViewSonic XG270QG, a responsive IPS model.



At 60Hz, shown above, the UFO appears relatively broad without clear internal detailing. This reflects a significant degree of perceived blur due to eye movement and is tied to the 60Hz refresh rate – this is also observed on the reference shots. There are varying degrees of trailing behind the object, too, caused by weaknesses in pixel responsiveness. This is generally most pronounced for the dark background (top row) and quite pronounced for the medium background (middle row), but relatively slight for the light background (bottom row). Increasing the ‘Overdrive’ level cuts down on the trailing in a gradual fashion, with the ‘Strong’ setting showing the clearest improvement for all rows. There is a bit of overshoot (inverse ghosting), including some ‘shadowy’ trailing behind the UFO cockpit for the dark background that’s darker than the background shade. And a small amount of ‘halo’ trailing for the light background that’s a little brighter than the background shade. We’d consider ‘Strong’ optimal based on the pursuit photographs above, but in practice ‘Medium’ may be preferred due to lower overshoot levels. The pursuit photographs below show how things looked at 100Hz.



At 100Hz, shown above, the UFO now appears somewhat narrower and more sharply focused. This reflects a significant decrease in perceived blur due to eye movement. There are again varying levels of trailing behind the object. This is most pronounced for the dark background but also bold and extensive for the medium background. The ‘Overdrive = Strong’ is quite effective in reducing this, although it still remains as a ‘smear’ behind the UFOs for the dark and lesser extent medium background. The trailing is more extensive and bolder than at 60Hz due to the increased pixel response requirements of the higher refresh rate. These pixel responses were too weak for an optimal performance at 60Hz, let alone 100Hz – the pixel overdrive levels required to remove this degree of trailing would cause massive overshoot. We feel the ‘Strong’ setting is easily the best balanced here and this is confirmed by broader analysis using a wide range of pixel transitions as well. The pursuit photographs below show how things look ramped up further, to 144Hz.



At 144Hz, shown above, the UFO appears narrower with clearer internal detailing. This indicates a further decrease in perceived blur due to eye movement. There is a further significant increase in pixel response requirements as a result of the extra 44Hz, so the weaknesses in pixel responsiveness are a bit more apparent. The overall trailing characteristics are largely comparable to 100Hz for a given background colour and ‘Overdrive’ level. It’s again clear that ‘Strong’ is optimal, but there’s certainly some ‘smeary’ trailing behind for the dark background and to a slightly lesser degree the medium background. The ‘smear’ extends somewhat further back than at 100Hz, again due to the increased pixel response requirements for optimal performance here. The dark background of the AG273QCX shows somewhat more extended ‘smeary’ trailing here, whereas the medium background shows less bold ‘powdery’ trailing. In practice we noticed the ‘smeary’ trailing on dark transitions (explored shortly) more readily on the AG273QCX so slightly preferred the pixel response behaviour of the CQ27G2U (CQ27G2). The XG270QG, meanwhile, provides much faster pixel responses than either model for all transitions shown here and just has a small amount of ‘powdery’ trailing for the dark and medium background shown here.

As well as increasing refresh rate to minimise perceived blur due to eye movement, the monitor offers an alternative in the form of ‘MBR’ (Motion Blur Reduction). This is a strobe backlight setting that causes the backlight to pulse at a frequency matching the refresh rate of the display – either 100Hz, 120Hz or 144Hz. Sensitivity to this flickering varies and some may find it bothersome whilst others will notice accelerated eye fatigue when using the setting, even if the flickering isn’t actively bothersome to them. The pursuit photographs below were taken with the monitor set to 100Hz using MBR. A few reference screens are also shown for comparison, using their respective strobe backlight settings at 100Hz. The AOC C24G1 using MBR (Motion Blur Reduction) and set to what we consider its optimal setting for that. And the Dell S2417DG or AOC AG251FG using ULMB (‘Ultra Low Motion Blur’).

Note that the ‘Overdrive’ setting can be adjusted under MBR. However; ‘Strong’ is the most practical setting as the acceleration levels are otherwise too slow with significantly increased trailing for some transitions. So we’ll just focus on the ‘Strong’ setting here. Also be aware that setting the ‘Overdrive’ to ‘Boost’ is equivalent to using the ‘Strong’ setting and setting ‘MBR’ to ‘20’.



With MBR active, the main object is much narrower with clearer internal detailing – even when comparing to 144Hz with MBR disabled. The internal detailing is particularly impressive using a setting of ‘MBR = 20’ – in practice it was a bit clearer with ‘MBR = 10’ than captured in the image as the white notches could be counted quite easily and the segmentation was more apparent. But ‘MBR = 20’ still gave an edge in terms of how sharp and distinct the internal details appeared. This narrower and sharper focus to the main image indicates a significant decrease in perceived blur due to eye movement, which is the main purpose of strobe backlight settings like this. There is also a significant amount of trailing behind the object, fragmented due to the strobe nature of the backlight. These fragments (repetitions of the object) are due to the pixel responses not keeping up with the rigorous demands of the refresh cycle. The initial repetition is nearly as bold as the object itself in some places. They also appear in front of the object, more noticeably for ‘MBR = 1’ and ‘MBR = 20’. The all-encompassing term ‘strobe crosstalk’ is used to describe this fragmented trailing around the object. Because not all areas of the screen refresh simultaneously, the appearance of strobe crosstalk can differ depending on how high up or low down on the screen the movement is being observed. The reference shots don’t show this, but there is instead some overshoot due to the strong pixel overdrive used to speed up the pixel transitions. The image set below shows results with a slight bump up in refresh rate to 120Hz, MBR again active.



The ‘Boost’ setting maintains similar overshoot levels to ‘Strong’ for the light background. For the dark and medium backgrounds ‘Boost’ sits some way between ‘Medium’ and ‘Strong’, reducing the boldness of the fragmented trailing without introducing overshoot. We consider the ‘Boost’ setting optimal for this reason, but the imperfections (strobe crosstalk) are still rather eye-catching and impair motion clarity a lot more than in the reference shots. The images below show the monitor running with this ‘Boost’ setting but set to 100Hz and 120Hz, allowing comparison with the 144Hz MBR performance. The pixel overdrive settings and relative effect of the MBR level worked in much the same way at reduced frame rate, so we’re keeping the comparison a bit simpler here.



Things appear quite similar to 120Hz, with a slight improvement to clarity in places. The segmentation is more distinct, for example. As before the white notches of the UFO were countable even with ‘MBR = 10’, they appear more blended in the photo than in reality. But ‘MBR = 20’ was particularly impressive here, with very distinct segmentation and a particularly sharp appearance to the black dividing line of the segments. This was clearer to the eye than in the photos. The strobe crosstalk behaviour is similar, with the trailing more compact again but a greater number of fragments in some cases. They’re particularly distinct with ‘MBR = 20’ due to the strong overall clarity of this setting and quite distinct at ‘MBR = 10’. With ‘MBR = 1’ they blend together quite readily and appear more as a single long conventional ‘smeary’ trail instead. The reference shots show much less strobe crosstalk (C24G1) or some overshoot instead (AG251FG).

It’s important to note that strobe crosstalk varies at different areas of the screen. Not all areas refresh simultaneously, so its appearance can differ depending on how high up or low down on the screen movement is being observed. The images below show pursuit photographs running from the top to bottom regions of the screen, with the screen set to 144Hz and ‘MBR = 10’. Strobe crosstalk variation at different points was also observed at 120Hz and 100Hz and using ‘MBR = 20’ – but the end result was quite similar and we didn’t feel it was worthwhile documenting these observations.



You can see quite strong strobe crosstalk throughout the screen. Further up it is visible in front of the object as well as behind. Towards the middle it’s only visible behind (with a greater number of fragments). And lower down, only a single fragment is visible behind the object – but it’s very bold and essentially melds into the main object. Whilst this strobe crosstalk doesn’t make the MBR setting useless and it still serves a purpose, it does affect the overall clarity of the setting and makes it less effective or enjoyable to use than it could be. We explore this and some other aspects to consider using in-game examples at the end of this section.

Responsiveness in games and movies

On Battlefield V, where frame rate kept pace with the refresh rate, the monitor provided quite a fluid experience overall. There was a reasonably low level of perceived blur, mainly linked to eye movement and the refresh rate of the 144Hz refresh rate of the monitor. The monitor is outputting up to 2.4 times as much visual information per second as a 60Hz monitor or this monitor running 60Hz. The high frame rate and refresh rate combination also aided the ‘connected feel’, describing the precision and fluidity you feel when interacting with the game world. The low signal delay also helped in this respect. There were some weaknesses in pixel responsiveness that added to perceived blur. For scenes where light to medium-light shades dominated, most daylight scenes for example, there was a bit of what we’d call ‘light powdery’ trailing. Enough to add a bit of extra perceived blur, with a slight dusty trail behind objects. But one which disappeared quickly and stuck quite close to the object. Where some slightly darker shades were introduced, for example lush foliage or medium brown tree trunks, there was some ‘heavy powdery’ trailing which had more of a noticeable impact on perceived blur.

With even darker shades brought into the mix, there were more pronounced weaknesses. Outside under a dark sky or shaded interiors, dark painted objects and heavily shaded elements in daylight for example. The trailing took on a ‘smeary’ appearance in places, typical for VA models when observing such content. This trailing extends further back behind the object, has a more significant impact on perceived blur and can stand out as a weakness against much faster pixel transitions elsewhere. There was also what we’d describe as ‘break-up’ trailing, whereby some of the colourful hues contained in the object or background appeared to leach out a bit. Like wetting a page with water soluble ink on it. The weakest pixel transitions, which caused such behaviour, weren’t as widespread or severe on this model as some VA models we’ve come across. It’s worthwhile drawing some comparisons between this model, using our preferred ‘Strong’ setting and some other VA models we’ve tested, sticking mainly with AOC models for simplicity. This model compares favourably to the AG273QCX using its optimal ‘Overdrive’ setting due to some of the ‘smeary’ trailing for the darkest shades being less pronounced. But the pixel transitions aren’t as snappy, overall, as on the C24G1 using its ‘Medium’ setting. The ‘Strong’ setting on the C24G1 model shows a definite reduction in ‘powdery’ and ‘smeary’ trailing, but it comes at the expense of much more noticeable overshoot. We consider the C24G1 to be one of the more capable VA performers, so it sets a fairly high benchmark. The LG 32GK850G we tested using its ‘Faster’ response time setting (G-SYNC enabled) told a similar story. Really, we consider the CQ27G2U (CQ27G2) to be pretty middling for pixel responsiveness as far as VA models go. The section of video review below runs through the response performance of the monitor and includes some examples of these weaknesses.

We observed similar strengths and weaknesses on Shadow of the Tomb Raider. Dark areas and dark shades in general are common on this title, often intertwining with lighter shades. The ‘stand out’ weaknesses including some ‘smeary’ trailing was again observed, but as noted these weaknesses weren’t as widespread or extensive as some VA models. They were certainly there and have the potential to bother some users. It’s worth noting that weaknesses in pixel responsiveness don’t always manifest themselves with distinct trailing, either. For intricate mixtures of light and dark, such as a rocky wall with plenty of shadows and indentations or some vegetation, there’s a blending together of shades that essentially makes the textures appear dimmer than when there isn’t movement. Some of these shades will appear brighter when the movement ceases, so alternating between these two states can appear as a sort of flickering. Another factor which can bother some is overshoot, which only affected a slim number of transitions on this model. We observed this on both titles in places, where some medium to light shades combined – such as a light-coloured building against a bright sky. Or concrete blocks against sand. There was a bit of ‘halo’ trailing that stood out slightly due to the fact it was somewhat brighter than the object or background colour. This wasn’t extreme, though, as it wasn’t massively brighter than the object or background and was confined to a small number of transitions.

Video content was also observed, at a range of frame rates. This included ~24-30fps Netflix content and YouTube content at up to 60fps. For the higher frame rate content some of the weaknesses observed when gaming at higher refresh rates were there, although not as obvious due to the significantly lower pixel response requirements of the reduced frame rate. They didn’t really stick out in an obvious way and didn’t impede our general enjoyment of such content. With a further reduction in frame rate, for example with the ~24-30fps content, the weaknesses were minor. Generally difficult to notice and not something we’d worry about too much if you enjoy consuming such content. In fact comparing to the much faster TN model (Dell S2716DG) we were using just before and after, the improved image quality of the AOC was readily apparent whereas differences in pixel responsiveness were much less apparent for this low frame rate content.

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FreeSync – the technology and activating it

AMD FreeSync is a variable refresh rate technology, an AMD-specific alternative to Nvidia G-SYNC. Where possible, the monitor dynamically adjusts its refresh rate so that it matches the frame rate being outputted by the GPU. Both our responsiveness article and the G-SYNC article linked to explore the importance of these two elements being synchronised. At a basic level, a mismatch between the frame rate and refresh rate can cause stuttering (VSync on) or tearing and juddering (VSync off). FreeSync also boasts reduced latency compared to running with VSync enabled, in the variable frame rate environment in which it operates.

FreeSync requires a compatible AMD GPU such as the Radeon RX 580 used in our test system. There is a list of GPUs which support the technology here, with the expectation that future AMD GPUs will support the feature too. The monitor itself must support ‘VESA Adaptive-Sync’ for at least one of its display connectors, as this is the protocol that FreeSync uses. The CQ27G2U (CQ27G2) supports FreeSync Premium via DP 1.2a and HDMI 1.4 on compatible GPUs and systems. You need to make sure ‘Adaptive-Sync’ is set to ‘On’ in the ‘Game Setting’ section of the OSD. On the GPU driver side recent AMD drivers make activation of the technology very simple and something that usually occurs automatically. You should ensure the GPU driver is setup correctly to use FreeSync, so open ‘AMD Radeon Software’, click ‘Settings’ (cog icon towards top right) and click on ‘Display’. You should then ensure that the first slider, ‘Radeon FreeSync’ is set to ‘Enabled’ as shown below.



The AOC supports a variable refresh rate range of 48 – 144Hz. That means that if the game is running between 48fps and 144fps, the monitor will adjust its refresh rate to match. When the frame rate rises above 144fps, the monitor will stay at 144Hz and the GPU will respect your selection of ‘VSync on’ or ‘VSync off’ in the graphics driver. With ‘VSync on’ the frame rate will not be allowed to rise above 144fps, at which point VSync activates and imposes the usual associated latency penalty. With ‘VSync off’ the frame rate is free to climb as high as the GPU will output (potentially >144fps). AMD LFC (Low Framerate Compensation) is also supported by this model, which means that the refresh rate will stick to multiples of the frame rate where it falls below the 48Hz (48fps) floor of operation for FreeSync. The variable refresh rate range and LFC support mean this model is AMD FreeSync Premium certified, specifically. If a game ran at 28fps, for example, the refresh rate would be 56Hz to help keep tearing and stuttering at bay. This feature is used regardless of VSync setting, so it’s only above the ceiling of operation where the VSync setting makes a difference.

To configure VSync, open ‘AMD Radeon Software’. Click ‘Settings’ (cog icon towards top right) and click ‘Graphics’. The setting is listed as ‘Wait for Vertical Refresh’. This configures it globally, but if you wish to configure it for individual games click ‘Game Graphics’ towards the top right. The default is ‘Off, unless application specifies’ which means that VSync will only be active if you enable it within the game itself, if there is such an option. Such an option does usually exist – it may be called ‘sync every frame’ or something along those lines rather than simply ‘VSync’. Most users will probably wish to enable VSync when using FreeSync to ensure that they don’t get any tearing. You’d therefore select either the third or fourth option in the list, shown in the image below. Above this dropdown list there’s a toggle for ‘Radeon Enhanced Sync’. This is an alternative to VSync which allows the frame rate to rise above the refresh rate (no VSync latency penalty) whilst potentially keeping the experience free from tearing or juddering. This requires that the frame rate comfortably exceeds the refresh rate, not just peaks slightly above it. We won’t be going into this in detail as it’s a GPU feature rather than a monitor feature.



Some users prefer to leave VSync enabled but use a frame rate limiter set a few frames below the maximum supported (e.g. 141fps) instead, avoiding any VSync latency penalty at frame rates near the ceiling of operation or tearing from frame rates rising above the refresh rate. If you activate the ‘Frame Counter’ in the ‘Game Setting’ section of the OSD, this will display the refresh rate of the display and therefore indicate the frame rate if ‘FreeSync’ is active and the frame rate is within the variable refresh rate range of the display. The final point to note is that FreeSync only removes stuttering or juddering related to mismatches between frame rate and refresh rate. It can’t compensate for other interruptions to smooth game play, for example network latency or insufficient system memory. Some game engines will also show stuttering (or ‘hitching’) for various other reasons which won’t be eliminated by the technology.

FreeSync – the experience

As usual we tested the monitor with a range of game titles with FreeSync active, but we found the experience very similar on all of them. Any issues identified with FreeSync that were isolated to a specific title would indicate an issue with the game or GPU driver rather than the monitor, too. We’ll therefore just focus on one title for this section; Battlefield V. The graphics settings on that title provide suitable flexibility to test the full variable refresh rate range of the monitor. The Radeon RX 580 in our test system is far from a beast of a GPU, so with reasonable graphics settings it’s very difficult to maintain a solid 144fps. Without FreeSync enabled (VSync on), even slight dips below this would cause obvious (to us) stuttering. And if you have FreeSync disabled and also disable VSync, you have to deal with tearing due to a lack of synchronisation between the frame rate and monitor refresh cycle. The lack of tearing or stuttering with FreeSync was certainly very nice in our view and something those sensitive to such things will really appreciate. But individual sensitivity to such things varies.

As frame rate dipped further, perhaps because we were being more generous with graphics settings or because action in the scene intensified, we noticed a drop off in ‘connected feel’ and an increase in perceived blur. This is linked to the drop in frame rate, which isn’t something FreeSync can help with. But the lack of tearing and stuttering was a very nice bonus regardless of this. As frame rate dipped well into the double digits there were some more noticeable instances of overshoot, including ‘halo trailing’ that’s somewhat brighter than object or background. And a little ‘dirty trailing’ that’s marginally darker than the object or background. This overshoot wasn’t particularly widespread or obnoxious in our view, but some may prefer to use the ‘Medium’ setting for ‘Overdrive’ to cut down on it. You will then have a greater number of suboptimal pixel responses and more conventional trailing, even at these relatively low frame rates where pixel response requirements are looser.

As usual for a monitor with Adaptive-Sync, there isn’t variable overdrive that re-tunes and optimises pixel overdrive to a broad range of refresh rates. Proper variable overdrive is reserved for models with an actual G-SYNC module. Nonetheless, we don’t feel the ‘Strong’ setting was at all unusable so feel most users will probably be happy enough just using that setting. The overshoot was still relatively tame, certainly less of an eyesore than on some models where refresh rate dips. Where frame rate dipped below the floor of operation (48fps and 48Hz), LFC (Low Framerate Compensation) kicked in to ensure the refresh rate kept to a multiple of the frame rate. This kept things synchronised and kept tearing and stuttering at bay. There was a brief stuttering when this activated, but this isn’t something users should find bothersome unless things are frequently going above or below the LFC boundary. We also observed some flickering when passing the LFC boundary and also during large fluctuations in frame rate. This was relatively mild really and some degree of flickering is common on VA models in a VRR environment due to their voltage sensitivity.

Nvidia Adaptive-Sync (‘G-SYNC Compatible’)

As noted earlier, AMD FreeSync makes use of Adaptive-Sync technology on a compatible monitor. As of driver version 417.71, users with Nvidia GPUs (GTX 10 series and newer) and Windows 10 can also make use of this Variable Refresh Rate (VRR) technology. When a monitor is used in this way, it is something which Nvidia refers to as ‘G-SYNC Compatible’. Some models are specifically validated as G-SYNC compatible, which means they have been specifically tested by Nvidia and pass specific quality checks. With the CQ27G2U (CQ27G2), you need to connect the monitor up via DisplayPort and enable ‘Adaptive-Sync’ in the ‘Game Setting’ section of the OSD. When you open up Nvidia Control Panel, you should then see ‘Set up G-SYNC’ listed in the ‘Display’ section. Ensure the ‘Enable G-SYNC, G-SYNC Compatible’ checkbox and ‘Enable settings for the selected display model’ is checked as shown below. Press OK, then turn the monitor off then on again so that it re-establishes connection – the technology should now be active.



In the image above you can see that the monitor is validated as ‘G-SYNC Compatible’ (or you could, if Nvidia Control Panel displayed the entire text instead of cutting it off). This is supposed to indicate that the monitor has been specifically tested by Nvidia and passes specific quality checks. At time of review it was not listed as such on Nvidia’s website – the full certification process has quite a few steps to it and has been hampered by a certain global pandemic. The technology did work and offered a similar experience to AMD FreeSync where the refresh rate was above 100Hz (100fps). A slight difference to be aware of with G-SYNC Compatible Mode is that the floor of operation appeared to be 60Hz (60fps) rather than 48Hz (48fps). An LFC-like technology was supported, with the monitor sticking to a multiple of the frame rate with its refresh rate below 60fps.

Some flickering was observed, which was there even where frame rates were fairly stable, but particularly intense during significant fluctuations in frame rate. Including sudden drops of perhaps 30fps or more. We also experienced some ‘screen blanking’ issues below 100Hz (100fps), where a signal is lost and then regained. Causing the screen to briefly turn off then turn back on. We didn’t observe this with triple-digit frame rates and it was rare between 80-100fps. Below this it was quite common and annoying, however. We tested various graphics drivers (with clean install), various cables and ports on the GPU and this behaviour persisted. This also means that when the LFC-like frame to refresh multiplication technology kicks in, there will be quite a few frame rates that would cause issues. This wouldn’t be an issue if you can consistently maintain triple digit frame rates. But even if you’re there most of the time, there can be occasional unforeseen dips below that could cause the screen blanking issues. We tested two different units and observed this same behaviour. There are quite a few positive comments from users regarding the ‘G-SYNC Compatible Mode’ experience on this model, including on our forum. A notable difference is that our test system uses an Nvidia GTX 1080 Ti, whereas the user in our thread is using a newer generation of GPU (GTX 2070 Super). An alternative Nvidia GPU wasn’t available for us to test with at time of review, but having extensively researched this issue on this monitor and a few others there seems to be a connection between presence of ‘screen blanking’ and flickering issues and GPU series used. It’s the older generation GPUs that seem to face these issues.

Our suggestions regarding use of VSync also apply, but you’re using Nvidia Control Panel rather than AMD Radeon Settings to control this. The setting is found in ‘Manage 3D settings’ under ‘Vertical sync’, where the final option (‘Fast’) is equivalent to AMD’s ‘Enhanced Sync’ setting. You’ll also notice ‘G-SYNC Compatible’ listed under ‘Monitor Technology’ in this section, as shown below. Make sure this is selected (it should be if you’ve set everything up correctly in ‘Set up G-SYNC’).



Finally, note again that you can activate the ‘Frame Counter’ feature in the ‘Game Settings’ section of the OSD to show the current refresh rate. This will adjust as the frame rate of the content changes and match that if it’s in the main variable refresh rate window (60 – 144fps).

MBR (Motion Blur Reduction)

Earlier in the review, we introduced the ‘MBR (Motion Blur Reduction)’ feature, its principles of operation and how it performs using specific tests. When using MBR or a similar strobe backlight feature, you must have your frame rate synchronised properly with the refresh rate of the display. If that isn’t the case you’re left with extremely obvious stuttering or juddering. This stands out in a particularly obvious way because there’s very little perceived blur due to eye movement to mask it. You can’t use Adaptive-Sync at the same time as MBR. We tested this setting using a range of game titles, but we’ll just be focusing on Battlefield V at a solid 144fps and the monitor set to 144Hz for this section. The observations here are largely reflected with lower frame and refresh rate combinations (120Hz and 100Hz) and with different MBR settings. We found ‘10’ offered a nice balance between brightness and clarity, but individual preferences will vary.

The setting certainly reflected its namesake by reducing overall perceived blur. During rapid manoeuvres and sharp turns it was easier to pick out details in the environment and those all-important enemies. The experience was not ‘clean’ or by any means optimal as far as strobe backlight operation goes, however. There was noticeable crosstalk as highlighted earlier, with clear repetitions of objects at even fairly slow paces of action. These repetitions were sometimes reasonably faint but other times as bold or almost as bold as the main object, significantly upsetting clarity. The slowest pixel responses still gave the ‘smeary’ trailing, for dark shades, that we observed with MBR disabled. In fact it stood out more noticeably due to the overall reduction in perceived blur and looked quite out of place.

Additional considerations include that the backlight flickers at a frequency matching the refresh rate of the display. This could bother sensitive users and even if the flickering itself isn’t noticed, it can be accelerate visual fatigue. We also noticed some colourful flashes of cyan and magenta which was more noticeable at lower refresh rates, particularly at 100Hz where it was readily observed when moving our eyes. At 144Hz they were less obnoxious, but still observable at times such as when observing movement with slender light-coloured objects on the screen. These flashes were less intense and colourful than we’ve seen on some wide gamut models, perhaps because he colour gamut isn’t as wide in this case. Overall the MBR setting still has its place and some people may enjoy it for the competitive edge it gives in terms of reducing overall perceived blur. But most will probably want to stick to the regular operation of the monitor, with Adaptive-Sync also available and doing its thing.

The curve and resolution

We’ve now tested a wide range of curved monitors of different sizes and curvature. The CQ27G2U (CQ27G2) offers a 27” screen size and 1500R (moderate) curve. We didn’t find the curve difficult to adapt to and found it perfectly natural when using the monitor. It slightly draws you into the image a bit, but it doesn’t give the sort of distortion or ‘alien’ experience you might expect if you view images or videos of the monitor. These exaggerate the curve and give a poor idea of what to expect when you’re sitting in front of the monitor. The curve can potentially enhance viewing comfort as well. If you require geometric perfection or frequently sit to the side of the monitor rather than centrally, a flat monitor may make more sense. Otherwise, it’s not something you should be afraid of.

We’ve also had considerable experience with the 2560 x 1440 (WQHD) resolution on screens of various sizes. We feel it works nicely on a 27” screen, providing a good although not exceptional pixel density and decent amount of useful desktop ‘real-estate’. It also provides a good level of detail for games, suitably high resolution images and other content. The size can also be considered quite engrossing compared to smaller screens, but is usually easy to adapt to and doesn’t tend to feel overwhelming. The images below show the monitor in action on the desktop. As usual the curve appears exaggerated, so these images are just for illustrative purposes.

When gaming we found the curve quite similar to when on the desktop really, drawing you into the experience without feeling unnatural or uncomfortable. We tend to find the effect more noticeable on wider screens than this (particularly ‘UltraWides’) but compared to a 1800R curve on a screen of this size the curvature is a bit more of a feature. It’s actually quite easy to forget you’re even using a curved monitor when engrossed into the game. The effect is pretty subtle, but still there. The images below show a range of game titles running on the monitor. The curve is again exaggerated in the images and they don’t accurately reflect how the monitor appears in person. Either in terms of image quality or curvature. They’re just for illustrative purposes.

Interpolation and upscaling

It may be desirable or necessary to run the monitor at a lower resolution than the native 2560 x 1440 (WQHD). Perhaps for performance reasons, or because a system is being used (such as games console) that doesn’t support the native resolution. The monitor supports scaling via any of its display inputs at various resolutions, including 1920 x 1080 (Full HD) at a range of refresh rates. These refresh rates were shown at the end of the ‘features and aesthetics’ section in the ‘Ultra HD, HD, SD’ list and include; 50Hz, 59Hz, 60Hz, 119Hz and 120Hz. To ensure the monitor rather than GPU is handling the scaling process, as a PC user, you need to ensure the GPU driver is correctly configured so that the GPU doesn’t take over the scaling process. For AMD GPU users the monitor will handle the scaling by default, when gaming at non-native resolutions. Nvidia users should open the Nvidia Control Panel and navigate to ‘Display – Adjust desktop size and position’. They should ensure that ‘No Scaling’ is selected and ‘Perform scaling on:’ is set to ‘Display’ as shown below.

The monitor offers various scaling options under ‘Image Ratio’ in the ‘Extra’ section of the OSD. These can only be adjusted if Adaptive-Sync is disabled, otherwise the default ‘Wide’ setting is used. This means that the monitor uses an interpolation process to map the selected resolution onto all 2560 x 1440 of its pixels. With Adaptive-Sync disabled you have access to a range of other settings here, the most useful of which is probably ‘1:1’, a pixel mapping feature which only uses the pixels called for in the source resolution. Presenting the image without distortion, but with a large black border around it. These settings are covered in this section of the OSD video. When running the 1920 x 1080 (Full HD) resolution and using the monitor’s full interpolation process (default ‘Wide’ setting), the monitor provides an image that’s somewhat softer than on a native 27” Full HD monitor. Things aren’t as soft as they sometimes look with monitor interpolation, though, neither do things look artificially over-sharpened. We feel quite a nice balance is struck here and the monitor is quite useable at non-native resolutions such as this. Although some sort of user sharpness control as you’d see on models like the BenQ EX2780Q would’ve been nice for some fine-tuning according to preferences.

As usual, if you’re running the monitor at 2560 x 1440 and viewing 1920 x 1080 content (for example a video over the internet or a Blu-ray, using movie software) then it is the GPU and software that handles the upscaling. That’s got nothing to do with the monitor itself – there is a little bit of softening to the image compared to viewing such content on a native Full HD monitor, but it’s not extreme and shouldn’t bother most users.

Video review

The video below shows the monitor in action. The camera, processing done and your own screen all affect the output – so it doesn’t accurately represent what you’d see when viewing the monitor in person. It still provides useful visual demonstrations and explanations which help reinforce some of the key points raised in the written piece.

Timestamps:
Features & Aesthetics
Contrast
Colour reproduction
Responsiveness

Conclusion

The AOC CQ27G2U offers a combination that many find very attractive – 27” screen size, 2560 x 1440 (WQHD) resolution and high refresh rate. This gives a decent amount of desktop ‘real-estate’ and provides good clarity potential for a wide range of content. The monitor also adopts a 1500R curve, a little steeper than older 1800R models with similar panels. This made the experience a touch more engrossing, but it wasn’t a radical change in that respect. The curve itself was quite easy to forget about entirely when using the monitor normally – which could be considered a good thing by many. Some positive tweaks were made to the subpixels, too, so it wasn’t just the case of curving the screen a bit more. This model avoided the partial subpixel illumination and relatively wide gaps below and above pixels. This normal RGB layout offers enhanced clarity to text and slender edges and also eliminated ‘static interlace patterns’. The monitor had some subtle ‘gamer’ touches, although these came in the form of some dark metallic red elements that were quite well-blended in practice. The overall design was fairly understated as far as such things go, with good ergonomic flexibility added into the mix as well.

As a VA panel, contrast was a key strength. We measured pleasing static contrast which helped improve the atmosphere in dark scenes and improved the depth of dark elements in mixed scenes. There was some ‘VA glow’ that could be observed for darker content in dimmer conditions, eating away at some of this atmosphere lower down the monitor. There was also some ‘black crush’ and perceived gamma shifts that affected detail levels for dark content. Regardless of this, we still found the overall contrast experience relatively pleasing and a good step up from competing IPS-type and TN models. The light matte screen surface was more pleasant to use than some, avoiding an obvious ‘layered’ appearance to things. It had slight graininess to it, but it’s unlikely to bother most users. The monitor provided fairly vibrant colour output, too, with some extension beyond the sRGB colour space (92% DCI-P3) injecting a bit of extra vibrancy and saturation. There were some losses of saturation towards the bottom and sides of the screen, from a normal viewing position. These were as low as we’ve seen from a VA model and significantly lower than the vertical saturation shifts on competing TN models.

The responsiveness was the usual mixed bag for a VA model. The 144Hz refresh rate was put to quite good use overall, with low input lag and some clear benefits in terms of both ‘connected feel’ and reduced perceived blur at high frame rates. Whilst some pixel responses made good use of the refresh rate, others didn’t. There were some weaknesses including ‘smeary’ trailing where dark shades were involved in the transition. There was little to complain about in the way of overshoot, though, and Adaptive-Sync did its thing to eliminate tearing and stuttering. This worked very well on our AMD GPU, but less so on our Nvidia GPU. There were some issues with slight flickering and ‘screen blanking’. These could potentially be fixed by Nvidia in a driver update and this issue is by no means unique to this model – from our research it seems newer Nvidia GPUs provide a much nicer ‘G-SYNC Compatible Mode’ experience. Overall, the monitor ticks plenty of boxes and one big one is the price. It’s significantly cheaper than many competitors, particularly those with IPS-type panels. Whilst the weaknesses we’ve exposed mean it’s not ideal for fast-paced gameplay or for colour critical work, it’s certainly a screen that will keep more casual gamers happy. It’s also a screen that works well for movie watching and productivity – a pretty capable monitor for the price.

The bottom line; a well-priced and flexible solution with an emphasis on strong contrast.

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