Acer XB323U GP

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 any static interlace patterns on this model. Under certain conditions we observed some dynamic ‘interlace pattern artifacts’, fine interlaced vertical lines during movement or when scanning our eyes across the screen in a certain way. They weren’t readily apparent unless the refresh rate was ~100Hz or below, becoming more noticeable at refresh rates of ~60Hz or lower. Even at relatively low refresh rates including 60Hz they were still quite faint and easy to ignore, though. Unless you’re sitting quite close to the screen and are sensitive to them. Most users will either not notice them or not find them bothersome, even at low refresh rates like 60Hz.

Responsiveness

Input lag

A small utility called SMTT 2.0 was used alongside a sensitive camera to analyse the latency of the XB323U GP, with over 30 repeat readings taken to help maximise accuracy. Using this method, we calculated 3.79ms (around 2/3rds of a frame at 170Hz) of input lag. The input lag measured was identical with ‘Ultra-Low Latency’ enabled or with Adaptive-Sync enabled, which greys this setting out and forces it on. The input lag measured here wasn’t significantly affected by refresh rate. It’s influenced by both the element you ‘see’ (pixel responsiveness) and the main element you ‘feel’ (signal delay). It indicates a low signal delay which most users should be happy with. Note that we don’t have the means to accurately measure input lag with Adaptive-Sync active in a VRR environment or with HDR active in an HDR environment.

Perceived blur (pursuit photography)

Our article on responsiveness explores some of the key concepts related to monitor responsiveness. Chief amongst these factors is the notion of perceived blur. This is contributed to by both the pixel responsiveness of the monitor and the movement of your eyes as you track motion on the screen. Perceived blur due to eye movement is the dominant form of perceived blur observed on a modern monitor, but both factors play an important role. We also look at a photography technique called ‘pursuit photography’, which uses a moving rather than static camera to capture motion in a way that reflects both aspects of perceived blur. This contrasts with static photos or videos which 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 and sufficient to highlight any weaknesses. The monitor was tested at 60Hz (directly below), 120Hz, 144Hz and 165Hz using all ‘Over Drive’ pixel response time settings. The ‘Over Drive’ is locked using Adaptive-Sync and optimised just slightly differently, so this was tested separately. This behaviour isn’t influenced by the ‘Over Drive’ setting used before enabling Adaptive-Sync and can’t be changed using the Display Widget software, either. 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 ViewSonic XG270QC, a 27” high refresh rate VA offering. The second reference is the ViewSonic XG270QG, a responsive IPS model.

Note that wavy patterns surrounding some UFOs in the background are slight image retention. This was only observed during this test and is something we’ve seen on various monitors before. It disappeared after using the monitor normally for several minutes.



At 60Hz, shown above, the UFO appears relatively broad without clear internal details. This reflects a significant degree of perceived blur due to eye movement and is tied to the 60Hz refresh rate. There are also varying degrees of trailing behind the UFOs due to weaknesses in pixel responsiveness. There’s actually very little in the way of conventional trailing. The ‘Off’ setting is actually very well-suited for 60Hz, providing ‘clean’ results that are actually slightly better than even the fast IPS-type reference screen. Increasing the ‘Over Drive’ setting really just serves to introduce overshoot. This was quite strong even using the ‘Normal’ setting, with clear colourful bright trailing behind with a bright or otherwise inky appearance. This is strengthened further using the ‘Extreme’ setting. ‘Adaptive-Sync = On’ locks into a setting that’s most similar to ‘Normal’, although the overshoot is a touch weaker. So moderately strong, but not extreme. We consider ‘Off’ the optimal setting at 60Hz, provided you’re able to adjust the setting as you’re not using Adaptive-Sync. The pursuit photographs below show how things looked with refresh rate doubled, to 120Hz.



At 120Hz, shown above, the UFO now appears significantly narrower with somewhat clearer internal detailing. This indicates a significant reduction in perceived blur due to eye movement. There are again varying degrees of trailing behind the UFOs due to weaknesses in pixel responsiveness. The ‘Off’ setting provides quite a clean performance, although a bit of ‘powdery’ trailing is introduced now due to the increased pixel response requirements of the doubled refresh rate. Particularly for the dark background (top row) and a bit for the medium background (middle row). This is reduced compared to the fast IPS-reference and in a different league to the VA reference. The ‘Normal’ setting removes the ‘powdery’ trailing but introduces some overshoot – not extreme, but certainly something sensitive users would notice. The ‘Extreme’ setting ramps this up so it’s very obvious. We consider ‘Off’ or ‘Normal’ optimal here depending on your overshoot tolerance. ‘Adaptive-Sync = On’ is essentially a slightly less aggressive version of the ‘Normal’ setting and we feel it strikes a nice balance. The pursuit photographs below show how things look with refresh rate bumped up just a little to 144Hz.



At 144Hz, shown above, the UFO appears just slightly narrower with slightly clearer internal detailing. This is a much smaller bump up in refresh rate than before, so the differences aren’t as pronounced. The pixel response behaviour is quite similar to before. The ‘powdery trailing’ with the ‘Off’ setting is now increased just slightly due to the raised pixel response requirements for an optimal performance. It’s improved compared to even the fast reference screen, however. The ‘Normal’ setting again gets rid of this and introduces some overshoot – it’s slightly less noticeable than at 120Hz as well. The ‘Extreme’ setting again sticks by its namesake with the level of overshoot that’s introduced. We consider ‘Normal’ optimal here, although users sensitive to overshoot may prefer ‘Off’. ‘Adaptive-Sync = On’ provides a rather clean performance here, further cutting down the overshoot whilst still providing the very rapid pixel responses required for a very competent 144Hz performance. The pursuit photographs below show how things look increased further, to 170Hz.

At 170Hz, shown above, the UFOs appear slightly narrower and more sharply focused again. This is due to a further decrease in perceived blur due to eye movement. The trailing behind the UFOs is not dramatically different to 144Hz, although the further increase in pixel response requirements make the ‘Off’ setting even less suitable now. There’s a further increase in ‘powdery’ trailing. And considering a broader range of transitions, as you’d observe whilst gaming, this translated into more noticeable perceived blur compared to using the ‘Normal’ setting. The overshoot levels with the ‘Normal’ setting are further decreased compared to 144Hz. There’s just a slight ‘shadowy’ trail behind the UFO for the medium background pus a little bright ‘halo’ trailing. The ‘Extreme’ again ramps up the overshoot so it’s very eye-catching. We consider ‘Normal’ optimal here – the ‘Adaptive-Sync = On’ state is again like this with slightly cut-down overshoot. With this, there’s just the faintest whiff of ‘powdery’ trailing introduced particularly for the dark background – but even that is very slight indeed. The overall balance here is exceptional, with very low overshoot and no real conventional trailing to speak of. A very convincing 170Hz performance in this test, something that’s shared under our broader analysis shortly.

Responsiveness in games and movies

On Battlefield V the monitor provided a fluid experience, with the frame rate keeping pace with the 170Hz refresh rate. Compared to a 60Hz monitor (or this monitor running at 60Hz), the monitor is outputting nearly 3 times as much visual information every second. Coupled with the low input lag, this provided an excellent ‘connected feel’ – the fluidity and precision that’s felt when interacting with your character on the game. As demonstrated earlier with Test UFO, there’s also a significant decrease in perceived blur due to eye movement. This gives a significant competitive edge in titles like this and is something that can improve the general experience and for some viewing comfort even during non-competitive gaming. The edge in ‘connected feel’ and decrease in perceived blur compared to the 144Hz (at 144fps) experience was not dramatic, but is still something we could notice and appreciate. Sensitivity to these things varies amongst individuals and we’d still say the initial increase from 60Hz to 120Hz or so, at suitable frame rates, is more dramatic.

The monitor also provided an impressively strong pixel response performance. The vast majority of pixel transitions were performed very well, so they didn’t significantly increase perceived blur even at the relatively demanding 170Hz refresh rate. There were the faintest whiffs of ‘powdery’ trailing for a select few transitions. For example, those involving very bright shades such as white against medium-dark backgrounds. But this was too faint to stand out or have a clear negative impact on overall perceived blur. In this respect the monitor performed better than some already rather fast IPS-type models such as the ViewSonic XG270QG and similar models sharing the panel. And they’re no slouches. Disabling Adaptive-Sync and sticking with the ‘Over Drive = Normal’ setting didn’t have any real impact on this ‘powdery trailing’, but it’s such a minor thing either way that it would be splitting hairs to even compare these two settings. There was no significant overshoot to speak of, just a little bit of bright ‘halo’ trailing in places that’s slightly lighter than the object or background shade. For example a light metal post against a bright sky. We didn’t find this eye-catching at all. Disabling Adaptive-Sync slightly increases overshoot, but this remains relatively light and something most users would find unbothersome or even unnoticeable.

The monitor provided a similarly impressive experience on Shadow of the Tomb Raider. No real issues of note, just a very convincing 170Hz performance. Just a whiff of overshoot or powdery trailing in places, but this was too slight to draw in the eye or detract from the gameplay. Things were impressively well-tuned with Adaptive-Sync enabled, whilst disabling it and sticking to the ‘Normal’ setting provided a largely similar experience. Differences that most would struggle to spot, such as a slight increase in overshoot but nothing substantial. We also observed movie content at a range of frame rates, including ~24 – 30fps and 60fps content. There were no clear weaknesses here, with the visual fluidity limited by the frame rate itself rather than the monitor.

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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 XB323U GP supports FreeSync via DP on compatible GPUs. Note that HDR can be activated (at the same time as FreeSync) via DP 1.4. You need to make sure ‘Adaptive-Sync’ is set to ‘On’ in the ‘Gaming’ section of the OSD. On the GPU driver side recent AMD drivers make activation of the technology very simple. 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, ‘Adaptive-Sync Compatible’ is set to ‘Enabled’ as shown below. Note that the driver doesn’t specifically refer to this as ‘FreeSync’. This is just a technicality – the monitor isn’t officially FreeSync certified, but it doesn’t affect how the monitor performs in its VRR window. The top image shows the monitor connected by DP and the bottom image by HDMI.

The Acer supports a variable refresh rate range of 55 – 170Hz*.. This means that if the game is running between 55fps and 170fps, the monitor will adjust its refresh rate to match. When the frame rate rises above 170fps, the monitor will stay at 170Hz 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 170fps, 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 >170fps). 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 55Hz (55fps) floor of operation for FreeSync. If a game ran at 32fps, for example, the refresh rate would be 64Hz 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. 167fps) 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 ‘Refresh Rate Num’ setting in the ‘Gaming’ 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.

*If you click on ‘Display Specs’ in the ‘Display Options’ screen that’s shown in the first image above, it lists 48 – 170Hz as the ‘AMD FreeSync Refresh Rate’ at the bottom. In our testing the floor of operation appeared to be 55Hz (55fps) rather than 48Hz (48fps) at 170Hz. Or 52Hz (52fps) if the monitor was set to 120Hz and 50Hz (50fps) if set to 100Hz. That’s when LFC appeared to kick in as tested in various scenarios.

FreeSync – the experience

We used this monitor on various game titles with FreeSync enabled. As usual, the experience was very similar on all of these titles. If any issues were identified on one title but not another, it would also indicate an issue with the game or GPU driver rather than the monitor. For simplicity we’ll just use one title as an example here; Battlefield V. The flexibility offered with the graphics settings on the game allows a broad range of refresh rates to be tested. The Radeon RX 580 used for this testing isn’t the most capable card out there, so it’s very difficult to maintain a solid 170fps at the WQHD resolution. As such, dips below this are all but inevitable. Without FreeSync enabled, these dips result in obvious tearing (VSync disabled) or obvious stuttering (VSync enabled). Obvious to us, at least, and others sensitive to such things. We appreciated having such disruptions removed by allowing FreeSync to do its thing.

As frame rate dipped a fair bit, let’s say to 100fps or so, there was a drop off in ‘connected feel’ as well as an increase in perceived blur that accompanied the loss of frame rate. This isn’t something FreeSync will correct, the frame rate reduction is still there all the same. However; the lack of tearing and stuttering from frame rate and refresh rate mismatches could still be appreciated. The monitor lacks variable overdrive, meaning the pixel overdrive is best tuned to the maximum refresh rate supported by the monitor (170Hz). As the refresh rate drops, alongside frame rate in this case, there is an ever-increasing level of overshoot. The pixel response times aren’t slackened off as they ideally would be. By around 100fps this was certainly more noticeable than at significantly higher frame rates, with some bright ‘halo’ trailing in places that might catch the eye at times. We certainly wouldn’t call this extreme, however.

As frame rate dipped further and was comfortably into the double digits, closer now to 60fps, this overshoot increased and became eye-catching in places. We wouldn’t describe it as extreme, but as we pointed out earlier setting overdrive to ‘Off’ would work better in such situations. Yet you don’t have that flexibility with Adaptive-Sync active. The way things work there is therefore not ideal, but for most will be quite acceptable – more so if most of the time is spent in the triple digits for frame rate. The drop off in ‘connected feel’ and increased perceived blur was also significant by this stage. When frame rate dipped below the floor of operation for the monitor, which appeared to be 55Hz (55fps) in our testing with 170Hz selected, LFC (Low Framerate Compensation) kicked in. This kept tearing and stuttering at bay by ensuring the refresh rate of the monitor stuck to a multiple of the frame rate. There was a bit of stuttering when LFC activated or deactivated, which is something we always observe with this technology. But if you’re only occasionally passing the boundary, it isn’t something to worry about. It could be annoying if you’re frequently passing the boundary, though.

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’. The Acer is amongst models which are specifically validated as G-SYNC compatible, which means it has been specifically tested by Nvidia and passes specific quality checks. With the XB323U GP, you need to connect the monitor up via DisplayPort and enable ‘Adaptive-Sync’ in the ‘Gaming’ 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.



As noted previously and as highlighted in Nvidia Control Panel, this model has been specifically tested and validated as ‘G-SYNC Compatible’ by Nvidia. The experience using ‘G-Sync Compatible Mode’ on our RTX 3090 was very similar to the experience using AMD FreeSync on this model. We observed the same VRR range and an LFC-like frame to refresh multiplication technology was employed below that to keep tearing and stuttering from frame and refresh rate mismatches at bay. There was again a momentary stuttering as the boundary was crossed, as we observed with our AMD GPU as well.

Our suggestions regarding use of VSync also apply, but you’re using Nvidia Control Panel rather than AMD Radeon Software 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, remember that you can activate the ‘Refresh Rate Num’ setting in the ‘Gaming’ section of the OSD to display the current refresh rate of the monitor. This will reflect the frame rate if it’s within the main variable refresh rate window, with the additional fluctuations described above possible depending on your GPU. And as with AMD FreeSync, HDR can be used at the same time as ‘G-SYNC Compatible Mode’.

HDR (High Dynamic Range)

On an ideal monitor, HDR (High Dynamic Range) involves the simultaneous display of very bright light shades and very deep dark shades. The monitor should also be able to display a very broad range of shades between these extremes, including highly saturated and vivid shades alongside more muted ones. The monitor would ideally support per-pixel illumination (e.g. backlightless technology such as OLED) or failing that offer a very large number of dimming zones with precise control. A solution such as FALD (Full Array Local Dimming) with a good number of dimming zones, for example. This would allow some areas of the screen to show high brightness whilst others remain very dim. Colour reproduction is also an important part of HDR, with the ultimate goal being support for a huge colour gamut, Rec. 2020. A more achievable near-term goal is support for at least 90% DCI-P3 (Digital Cinema Initiatives standard colour space) coverage. Finally, HDR makes use of at least 10-bit precision per colour channel, so its desirable that the monitor supports at least 10-bits per subpixel.

The HDR10 pipeline is the most widely supported HDR standard used in HDR games and movies. And HDR10 is what’s supported here. Unlike most HDR-capable monitors, the Acer XB323U GP does not automatically switch into its HDR operating mode when an HDR colour signal is detected. You must do this manually – there are a few ways to do it, but we’d recommend setting ‘HDR’ to ‘Auto’ or ‘HDR-600’ in the ‘Picture’ section of the OSD. Inconveniently, other activation methods will set this to ‘Auto’ rather than ‘HDR-600’ (the latter being our preferred setting, as explored shortly). As of the latest Windows 10 update, relevant HDR settings in Windows are found in ‘Windows HD Color settings’ which can be accessed via ‘Display settings’ (right click the desktop). Most game titles will activate HDR correctly when the appropriate in-game setting is selected. A minority of game titles that support HDR will only run in HDR if the setting is active in Windows as well. Specifically, the toggle which says ‘Play HDR games and apps’. If you want to view HDR movies on a compatible web browser, for example, you’d also need to activate the ‘Stream HDR Video’ setting. These settings are shown below. Also note that there’s a slider that allows you to adjust the overall balance of SDR content if HDR is active in Windows. This is really just a digital brightness slider, so you lose contrast by adjusting it. Under HDR you lose access to many adjustments in the OSD, including gamma and colour channels. We’d recommend only activating HDR in Windows if you’re about to specifically use an HDR application that requires it, and have it deactivated when viewing normal SDR content on the monitor.

For simplicity we’ll simply focus on two titles for this section; Battlefield V and Shadow of the Tomb Raider. We’ve tested both titles on a broad range of monitors under HDR and we know they represent a good test for monitor HDR capability. The experience described here is largely dictated and limited by the screen itself. Although our testing here is focused on HDR PC gaming using DisplayPort, we made similar observations when viewing HDR video content on the Netflix app. There are some additional points to bear in mind if you wish to view such content. We also made observations using HDMI, which would be used when viewing HDR content on an HDR compatible games console for example, and things were very similar. Testing on both our Nvidia and AMD GPUs showed that the HDR implementation was similar in both cases, too. As usual for HDR, the settings available in the monitor are greatly restricted, including brightness being greyed out and colour channels being locked off. A sharpness filter called ‘Super Sharpness’ (found in the ‘Picture’ section of the OSD) is enabled by default. It’s usual for such a filter to be applied in HDR implementations to help accentuate some of the contrast and shade variety advantages of HDR. But you can disable it as we preferred doing for a more natural look.

The Acer XB323U GP is VESA DisplayHDR 600 certified. This is a ‘mid-range’ certification level for HDR and offers some significant improvements compared to the more basic VESA DisplayHDR 400 standard. A particularly important aspect of the DisplayHDR 600 certification that’s lacking with DisplayHDR 400 is that it necessitates local dimming on the backlight. As we explored in the contrast section, this model offers 16 dimming zones which provides a situational edge in contrast. More specifically, it has an edge-lit arrangement with 16 individually addressable LED clusters located along the bottom edge of the monitor. Light guides are used to split the screen into 16 dimming zones, as vertical ‘bands’ running along the screen. To use this functionality, ‘HDR’ needs to be set to ‘HDR-600’ in the ‘Picture’ section of the OSD. If it’s set to ‘Auto’ then no local dimming is used and the monitor sticks to a high brightness setting without Dynamic Contrast. The non-contrast HDR attributes remain intact. You need to be running with an HDR signal to use the local dimming as well, you can’t enforce it under SDR. We much preferred using the ‘HDR-600’ setting so will be focusing on that for the rest of this section.

The DisplayHDR 600 level also requires at least 90% DCI-P3 colour gamut coverage, which the Acer very comfortably exceeded with a recorded gamut of 95% DCI-P3 and significant extension beyond DCI-P3 in some regions. This is shown in the graphic below, which featured earlier in the review. The red triangle shows the monitor’s colour gamut, the blue triangle DCI-P3 and green triangle sRGB. The colour gamut provides a decent match to the DCI-P3 near-term target game developers have in mind for HDR content, plus a bit of a push beyond towards the longer-term Rec. 2020 target in some regions. The colour representation under HDR was pleasing, with an excellent variety of shades and appropriate saturation levels maintained throughout the screen. There was an impressive array of lush greens alongside more muted pastel and minty green shades. And a nice array of rich (but nor ‘overdone’) earthy browns. The depth to some of these shades was beyond what we’d typically see under HDR on a monitor, even one with decent DCI-P3 coverage – but the excessive red hues for reddish browns or excessive yellow hues for yellowish greens we observed under SDR were thankfully absent. This gave the environments on both titles an enticing look – lively but still natural. Where the developers intended strong saturation to be shown, the monitor certainly delivered. Roaring fires showcased some impressively rich yellows and oranges, without being overpowered by the reddish oranges we saw under SDR. There were some exceptionally eye-catching blue flowers and colourful painted pottery on Shadow of the Tomb Raider, too, showcasing some shades that are well beyond the confines of sRGB and in some cases beyond DCI-P3 as well.

Colour gamut 'Test Settings'

The HDR10 pipeline makes use of 10-bits per colour channel, which the monitor supports via 8-bit + FRC. At 120Hz+ via HDMI the dithering stage is offloaded to the GPU at the native resolution, for bandwidth reasons. We’ve carefully observed a range of content (including fine gradients) on a broad range of monitors where 10-bit is supported monitor side (usually 8-bit + FRC) and where the GPU handles the dithering under HDR. Including comparisons with a given model where the monitor handles the dithering at some refresh rates and the GPU handles it at others. Regardless of the method used to achieve the ’10-bit’ colour signal, the visual output at the end of it all is very similar. It’s possible some subtle differences might be picked up during a careful side by side comparison of very specific content, but the difference really isn’t clear. The 10-bit colour signal enhances the nuanced shade variety, bringing advantages to the display of shades at both the high end low ends. Weather effects, smoke, sky and other fine gradients are handled with superior precision and showcase smoother and more natural progressions than observed under SDR. A broader range of closely matching dark shades makes shaded areas appear more natural or ‘believable’ as well, lifting out some subtle details and keeping things defined in a way that simply isn’t observed under SDR. The following image shows a scene from Shadow of the Tomb Raider which we find particularly good at highlighting a strong HDR performance. Remember that the photo is purely for illustrative purposes and in no way represents how the monitor appeared running HDR in person.

This scene highlighted the enhanced precision (10-bit colour) with some very fine and natural-looking gradients – including the light streaming in from above and the mist surrounding that area. The definition of shaded areas and natural appearance of those was also improved. This scene was also good at highlighting the advantages of local dimming on this monitor, alongside the powerful backlight and relatively high luminance levels it can pump out. The glint of light on the water was immediately eye-catching, as was the bright light streaming in from above. The dimming zones covering such content were fired up to very high levels, whilst dimming zones covering the more muted content such as the mixed vegetation and shaded areas of water were much dimmer. The result was bright elements that stood out very nicely without compromising the entire scene. Obviously 16 dimming zones isn’t a huge number to have on such a large screen, so the precision here is limited. Some darker shades are dragged up so they’re brighter than they should be and this shifts around the screen as the scene changes. Focusing on predominantly dark scenes with some brighter shades mixed in reveals these shortcomings quite clearly, with the depth of some of the dark shades clearly raised above what it should be for large sections of the screen. But some shades still remain significantly deeper than they would if the entire backlight was lit up as strongly as those bright dimming zones. It’s a nice situational boost in contrast, in our view, giving a more believable look to daylight scenes and helping bright elements stand out better with darker surroundings. It’s just part of a relatively strong overall HDR performance from the Acer. It can’t perform miracles, but it’s a good few steps beyond what you usually get from the HDR experience of a monitor. The HDR experience using Shadow of the Tomb Raider as an example is explored in the section of video review below. This video section includes some discussion of our HDR experiences on Netflix, which we enjoyed using with HDR enabled on the monitor as well.

The 32″ 2560 x 1440 experience

With a 2560 x 1440 (WQHD) resolution spread across a 32” screen, the pixel density of the monitor is 91.79 PPI (Pixels Per Inch). That’s somewhat lower than the pixel density of a 27” WQHD model (108.79 PPI) and vastly lower than a 32” ‘4K’ UHD model (137.68 PPI). You don’t get the same clarity and detail potential as these tighter pixel densities, with a particular gulf compared to the UHD screens of this size. But the Acer has the same pixel density as a 24” Full HD monitor, which many users are quite comfortable with. It’s by no means a poor pixel density and it’s really at a level that many users will be happy with in terms of detail and clarity plus the relative size of UI elements and text without scaling. The size of the screen is also attractive in terms of creating an immersive experience – we found it engrossing from our preferred viewing distance of ~70cm (or a bit further back depending on seating position and posture). But didn’t find it overwhelming. The images below give an idea of the desktop real-estate and multi-tasking potential that’s offered by the screen. It’s in no way an accurate representation of how the screen is to view in person, but provides a nice visual indication of how much information you can cram onto the screen.

The size also means you can move further back if you wish, using the screen for gaming (and indeed other tasks) from a distance. Viewing a movie or gaming on a console on the couch or your bed, for example. We found the gaming experience engrossing whilst sitting at a desk – and whilst we prefer tighter pixel densities ourselves, finding ‘4K’ UHD models of this size particularly rewarding, the pixel density still didn’t strike us as ‘poor’ by any means. With detail levels cranked up we felt this screen was a very nice ally for our newly purchased RTX 3090. The photos below are again just here to fire up your imagination and don’t accurately represent how the monitor appears in person. They show a range of game titles running on the monitor.

Interpolation and upscaling

It may be desirable or indeed necessary to run the monitor below its native 2560 x 1440 (WQHD) resolution. Perhaps for performance reasons, or because a system such as a games console is being used that doesn’t support the WQHD resolution. The monitor provides scaling functionality via both DP and HDMI. It can be run at resolutions such as 1920 x 1080 (Full HD) and can use an interpolation (scaling) process to map the image onto all pixels of the screen. The monitor only supports interpolation at up to 60Hz, at higher refresh rates the GPU or system would need to handle the scaling process. 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 driver is set up correctly by default to allow the monitor to interpolate where possible. Nvidia users should open Nvidia Control Panel and navigate to ‘Display – Adjust desktop size and position’. Ensure that ‘No Scaling’ is selected and ‘Perform scaling on:’ is set to ‘Display’ as shown in the following image.

The monitor offers various scaling settings under ‘Wide Mode’ in the ‘System’ section of the OSD: ‘Full’, ‘Aspect’ and ‘1:1’. The ‘Full’ setting will make sure all 2560 x 1440 pixels of the screen are active, whilst the ‘Aspect’ setting will use as many pixels whilst maintaining the aspect ratio of the source resolution. A black border will fill out any unused pixels. The ‘1:1’ setting is a pixel mapping feature which will only use the pixels called for in the source resolution and display a black border around the image. These scaling settings are demonstrated in the OSD video. When running the 1920 x 1080 (Full HD) resolution and using interpolation on the monitor, the image appears noticeably softer than it would on a native Full HD screen of this size. The pixel density is admittedly quite poor on such a large Full HD screen, but the lack of clarity to textures and lack of definition of object edges in comparison to this was still noticeable. Activating ‘Super Sharpness’ in the ‘Picture’ section of the OSD offset this softening quite effectively, although things appeared somewhat filtered and over-sharpened. This is less apparent if sitting a little way back from the monitor, perhaps over 1m or so. This is better than some interpolation processes we’ve seen, but we’ve seen better and more flexible implementations as well. Having various adjustable sharpness levels can certainly help out when it comes to interpolation rather than a single fixed setting.

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
HDR (High Dynamic Range)
Responsiveness (General)
Responsiveness (Adaptive-Sync)

Conclusion

The engrossing nature of a ~32” screen like the Acer XB323U GP is very attractive to some, whilst the 2560 x 1440 (WQHD) resolution provides a comfortable pixel density. Not a spectacular one by any means, but similar to a 24” Full HD screen which many are comfortable with. It’s a resolution that isn’t overly demanding on mid-range GPUs, whilst providing a nice amount of desktop real-estate. Unlike many competing models, the screen on this one is flat rather than curved, which some will welcome. The monitor provided excellent ergonomic flexibility including a fairly generous amount of height adjustment and the ability to pivot the screen. The stand was solidly constructed, with a powder-coated metal finish and sculpted design. It gave a certain reassuring weight and robustness to the overall package.

The contrast was in-line with our expectations for the panel type and indeed the panel specifications. The static contrast was still a bit higher than some IPS-type models, but far from the main strength of the monitor. Without a high static contrast ratio and with ‘IPS glow’ eating away at the atmosphere when observing darker content under dimmer lighting. The screen surface had a ‘light misty’ graininess to it, but didn’t offer a layered appearance in front of the image. This is what we’d classify as ‘very light’ matte anti-glare, preserving clarity and vibrancy well. Speaking of vibrancy, that’s something this model delivered in droves. The colour gamut was very generous indeed, much more so than you might think if simply looking at DCI-P3 coverage and comparing that to other models. Plenty of extension beyond even that gamut in some regions, full Adobe RGB coverage and a bit beyond. This gave sRGB content a clearly saturated and highly vibrant look, which suits some but not others. It also provides a good spread of gamuts you can use if profiling the monitor for colour-critical purposes. The strong colour-consistency also aided things there as well as improving the overall impression of the image, without clear saturation shifts at different points of the screen. For those who prefer sRGB content such as games to look more as the developers intend, an sRGB emulation setting is included. This cut down the gamut appropriately and didn’t lock off brightness control as some such settings do.

The HDR support was a good step above what most monitors offer. The monitor includes 16 dimming zones which were highly reactive and responded readily to significant changes in scene brightness for that particular zone. Whilst this isn’t sufficient to allow the monitor to display intricate mixtures of light and dark and is a tiny number compared to the ~3.7 million pixels of the monitor, it still gave a noticeable situational boost in contrast. The backlight was powerful enough to pump out over 700 cd/m² – with local dimming in place, the brightest content appeared very eye-catching without the dimmer areas appearing as ‘flooded’ as they otherwise would. The generous colour gamut was also put to good use under HDR, delivering a good dose of vibrancy where it should be whilst keeping more natural and pastel shades appropriately muted.

A convincing 170Hz performance was also delivered by the monitor, with fast and well-tuned pixel responses and low input lag helping round things off there. The monitor also supports Adaptive-Sync, working well under both AMD FreeSync and with Nvidia’s ‘G-SYNC Compatible Mode’. The response time setting being locked off meant you were stuck with increasing levels of overshoot were observed as refresh rate decreased, which occurs alongside frame rate reduction with Adaptive-Sync active. It would’ve been nice to have some flexibility there, or better yet effective and well-implemented variable overdrive. The monitor doesn’t offer any strobe backlight technology, either, even if that’s something which only a select few users would enjoy using anyway. Outside of PC usage, the monitor supports 120Hz via HDMI plus the full HDR capability. Which makes it a nice option for suitable games consoles like the Xbox Series X. It’s worth noting, though, that FreeSync is not supported over HDMI – not something we see as essential, especially for console gamers who are very used to regular VSync.

Overall, this monitor was an accomplished performer, offering a well-rounded experience under both SDR and HDR. It delivered a level of vibrancy and consistency to the image (gamma and saturation) that VA competitors simply can’t match. The responsiveness was also leagues ahead of most VA models, with an edge against even the strongest VA performers such as the Samsung Odyssey G7. Impressive for a VA model without question, but with some ‘heavy powdery trailing’ for some transitions that the Acer is completely free from. The contrast experience is obviously the main comparative weakness of the Acer, although the Samsung model is relatively weak for a VA model in that respect. Under HDR the experience is really more solid on the Acer as it has double the number of dimming zones, plus its superior colour credentials. The fact the Samsung model has a 1000R curve and the Acer has a flat screen will also be a defining point for some users. We also drew some comparisons with the ASUS PG329Q at various points of the video review, based on user feedback and our own research. It uses the same panel as the XB323U GP and therefore offers many similarities. A potential advantage of the ASUS includes variable overdrive and a strobe backlight mode, although we can’t say how well these features are implemented and simply including them means very little. You get an extra 5Hz of refresh rate on the ASUS, but that’s largely marketing one-upmanship. And it’s slightly cheaper in most markets. The factors in favour of the Acer include; DP 1.4 capability, a more solidly built and ‘premium feeling’ stand, superior stand adjustability (extra 30mm of height adjustment and pivotable) and brightness adjustment when using sRGB emulation. According to side by side testing, multiple users have reported better use of high brightness levels under HDR on the Acer as well.

The bottom line; a solid performer under both SDR and HDR, with strong vibrancy and a convincing 170Hz performance.

Positives	Negatives
Strong ‘out of the box’ gamma tracking and OSD flexibility, a very vibrant look to the image with a highly generous colour gamut and strong colour and gamma consistency	sRGB emulation setting doesn’t offer full OSD flexibility, a DCI-P3 emulation mode or something that slightly clamps the gamut might’ve been nice as well
Static contrast in-line with expectations, a ‘very light matte’ anti-glare screen preserves clarity and vibrancy well and a competent HDR performance	‘IPS glow’ ate away at atmosphere for darker scenes, ‘light misty’ graininess to screen surface and a greater number of dimming zones would be welcome
A solid 170Hz performance with well-tuned pixel responses and low input lag, Adaptive-Sync did its thing on both our AMD and Nvidia GPUs	Some overshoot, particularly as refresh rate dips – ‘Over Drive’ setting is locked with Adaptive-Sync active
Good ergonomic flexibility and a good premium feel due to stand design and material choice. Screen size and resolution provides an immersive experience with decent desktop real-estate and reasonable pixel density	Pixel density not particularly high when compared to 27” models with this resolution and moreover ~32” ‘4K’ UHD models

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