ViewSonic XG341C-2K

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.

In this case we observed some extremely faint static interlace patterns at ~144Hz and above, with some shades (mainly blue-biased) appearing with very fine lines of a very slightly darker and lighter variant of the intended shade. As faint as we’ve seen them whilst still being able to observe them. We also observed slight dynamic interlace patterns. More specifically, a fine polygonal mesh could be observed during movement at lower refresh rates. These were difficult to spot rather than obvious, even at relatively low refresh rates such as 60Hz and not observed above ~120Hz. They occurred regardless of VRR status and ‘Local Dimming’ etc. Neither artifact type was obvious on this monitor and aren’t something most will notice or find eye catching from a normal viewing distance at any refresh rate – but we like to note their existence for completeness.

Responsiveness

Input lag

A sensitive camera and a utility called SMTT 2.0 was used to analyse the latency of the XG341C-2K. Over 30 repeat readings were taken to help maximise accuracy. Using this method, we calculated 3.63ms (slightly above ½ a frame at 165Hz) of input lag. Similar input lag was recorded using ‘Local Dimming’. This figure is influenced by both the element of input lag you ‘see’ (pixel responsiveness) and the main element you ‘feel’ (signal delay). It indicates a low signal delay which most users should find acceptable. Note that we don’t have the means to accurately measure input lag with VRR technology active in a VRR environment or HDR active in an HDR environment.

Perceived blur (pursuit photography)

In our responsiveness article, we explore the key concepts surrounding monitor responsiveness. One of these is the concept of ‘perceived blur’, contributed to by both the movement of your eyes as you track motion on the screen and the pixel responses of the screen. This first factor is dominant on modern monitors, but both elements play an important role. A photography technique called ‘pursuit photography’ is also explored, which uses a moving rather than stationary camera to capture motion performance in a way that reflects both aspects of perceived blur. The images below are 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 good practical speed to take such photographs at and highlights both elements of perceived blur well. The UFOs move across the screen from left to right at a frame rate matching the refresh rate of the display. All three rows of the test are analysed to highlight a range of pixel transitions. The monitor was tested at 60Hz (directly below), 120Hz and 165Hz. All 5 ‘Response Time OD’ settings were tested. The two final columns show reference screens, set to what we consider their optimal response time setting for a given refresh rate. The AOC CQ32G3SU, which is a 165Hz VA model providing a fairly average (or slightly above average) pixel response performance for the panel type. Or the CU34G2X for results at 144Hz as this offers similar responsiveness to the CQ32G3SU but like the ViewSonic was tested at 144Hz. The other reference screen is the Gigabyte M27Q, which is an IPS model offering a decent but not outstanding pixel response experience – one which most are perfectly happy with.

At 60Hz, above, the UFO appears soft and unfocused without clear internal detailing. This reflects a moderate amount of perceived blur due to eye movement. Significant weaknesses are exhibited, including distinct ‘smeary’ trailing for the dark background (top row) in particular and less extensive but still ‘smeary’ trailing for the medium background (middle row). Performance for the light background (bottom row) is better. There is a slight reduction in this trailing going up from ‘Standard’ to ‘Fast’ and a slight further reduction in places going up to ‘Faster’. These differences aren’t particularly clear for the transitions shown here – they are somewhat clearer for some other transitions not shown, but even with the ‘Faster’ setting some distinct weaknesses remain. The ‘Ultra Fast’ and ‘Fastest’ settings appear to be ordered incorrectly in the OSD and named incorrectly as the ‘Fastest’ setting is actually slower than ‘Ultra Fast’. This was the case on our unit, at least – it may vary between units and firmware revisions. ‘Ultra Fast’ shows more distinct overshoot (inverse ghosting) in this test, with bright and colourful ‘halo’ trailing. In practice even the slightly slower ‘Fastest’ setting shows extreme overshoot for some transitions and we see little practical use for it. We therefore consider the ‘Faster’ setting optimal for 60Hz – both reference screens offer superior performance, however. Below you can see what things look like with refresh rate increased significantly to 144Hz.

We’d usually include results at 120Hz, but as covered near the end of the ‘Features and aesthetics’ section this isn’t supported correctly at the native resolution. Unless using DP with ‘FreeSync Premium Pro’ active – and that locks the brightness at unacceptably high levels for this testing. Based on visual assessment, though, performance at 120Hz was quite similar to what is shown below at 144Hz with only a marginal reduction in trailing length.

At 144Hz, above, the UFO appears significantly narrower with clearer internal detail. This reflects a significant decrease in perceived blur due to eye movement. To the eye the black lines which separate the segments of the UFO are less blended than they appear in the photos, so segmentation is more distinct – but the white notches still blend together. There’s a significant increase in the pixel response requirements for good performance here. The ‘smeary’ trailing is now bolder, particularly for the medium background where there is now a very bold and more extended look to the trailing. The relative impact of each of the ‘Response Time OD’ settings is similar to at 60Hz. Whilst ‘Fastest’ may appear optimal from these photos, in practice there is some very obvious overshoot using this setting for quite a broad range of transitions not shown here. Including ‘halo’ trailing that’s significantly brighter than the background and stands out in a clear way. We again consider the ‘Faster’ setting optimal, for 144Hz. The reference screens both outperform the ViewSonic – the IPS reference in particular, though the VA reference still shows less extended and bold trailing for the dark and medium backgrounds. Below you can see things with a slight boost in refresh rate up to 165Hz.

The M27Q IPS reference runs at 170Hz, but this makes a negligible difference compared to 165Hz. As noted earlier, using the ‘OverClocking’ feature allowed the ViewSonic to run at 200Hz but in our case also caused significant frame skipping so was excluded from our analysis. Based on casual observation it was clear the pixel responses were not providing an optimal 200Hz experience, anyway. Pixel response tuning was similar to at 165Hz and weaknesses were more apparent due to the increased pixel response requirements.

At 165Hz, above, the UFO appears slightly narrower with somewhat improved definition. To the eye the segmentation is quite distinct now, though the white notches still appear blended together as they appear in the photos. This reflects a further reduction in perceived blur to eye movement – a much less significant one than the initial more than doubling from 60Hz to 144Hz as it’s only an additional 21Hz in this case. The pixel response requirements for a good performance are slightly bumped up here, but the overall performance was quite similar to at 144Hz. The overshoot appears clearer for the ‘Fastest’ and moreover ‘Ultra Fast’ settings. In practice we found it problematic regardless of refresh rate, particularly for transitions not even assessed here. There were also overdrive artifacts observed, including over-sharpening during movement and interlaced patterns observed within the overshoot. For some transitions not shown with Test UFO, there are some clearer differences between ‘Fast’ and ‘Faster’ which become more noticeable under HDR. We’d consider ‘Fast’ or ‘Faster’ optimal depending on whether you want to sway things more towards reduced overshoot (especially under HDR) with ‘Fast’ or slightly improved pixel responses with ‘Faster’. These differences were also apparent at lower refresh rates so this is a more general observation than a 165Hz-specific one. Both reference screens again offered superior performance here for all backgrounds, but particularly the medium and dark backgrounds. Remember that these references are far from the fastest examples for their respective panel types, too.

The monitor includes a strobe backlight setting called ‘PureXP’ (“Pure Experience”), which we covered earlier with respect to brightness. This allows the backlight to flicker at a frequency matching the refresh rate of the display – with 100Hz (DP only), 144Hz and 165Hz selectable. 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. There are various levels of ‘PureXP’, with all levels explored here; ‘Light’, ‘Normal’, ‘Extreme’ and ‘Ultra’. We feel this and the ‘Response Time OD’ settings should just include numbered values instead of ambiguous and in some places misplaced wording. The higher the ‘PureXP’ level, the shorter the pulse width – meaning the ‘on’ phase of the strobe is shorter. This decreases brightness but can improve motion clarity. The pursuit photographs below were taken with the monitor set to 100Hz, 120Hz and 144Hz using ‘PureXP’. A few reference screens are also shown for comparison, where possible, using their respective strobe backlight settings. 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 AG254FG using ULMB (‘Ultra Low Motion Blur’).

Note that the ‘Response Time OD’ setting is unavailable when using ‘PureXP’. ‘FreeSync Premium Pro’ is not available, either, so Adaptive-Sync can’t be used at the same time. If you attempt to use HDMI 2.1 VRR at the same time (doesn’t require ‘FreeSync Premium Pro’ to be active in the OSD), fluctuations in frame rate provide extreme flickering and additional visual glitches – so VRR is not supposed to be used at the same time as ‘PureXP’.

Regardless of refresh rate, the setting was hampered by significant issues which prevented it from providing the sort of motion clarity improvement you’d hope for. If you just focus on the main object, it’s narrower with some more distinct detail and segmentation. To the eye segmentation is quite distinct, particularly at 144Hz and above. The white notches are more distinct and vaguely countable, but overlap in a messy way due to strong strobe crosstalk. This is a duplication of the main object which can appear either in front or behind of the main object – in this case it’s mainly in front and melds into the main object, greatly affecting motion clarity. The strobe crosstalk varies in position and intensity depending on how high up or down the screen you’re observing, but in this case it’s even strong centrally where your eyes mainly focus during the competitive play this sort of setting is designed for. There are also distinct repetitions behind the UFOs due to significant pixel response time weaknesses. For transitions not shown here, significant and widespread overshoot was also observed as bright and eye-catching fragments of ‘halo’ trailing. The reference screens perform significantly better here and actually offer potentially useful strobe backlight settings. In this case the ‘PureXP’ setting failed to achieve its main goal of improving motion clarity, even with the ‘Ultra’ level and where your frame rate matches the refresh rate perfectly – we found it visually distracting and uncomfortable to use for this reason. If the frame rate departs at all from the refresh rate, you’re met with significant and obvious stuttering which is normal for such a setting. Because of this poor performance and restrictions we’ve mentioned elsewhere in the review, we won’t be performing further assessment of this setting.

Responsiveness in games and movies

On various Battlefield titles, at a frame rate keeping up with the 165Hz refresh rate, the monitor provided a fluid feel to things. Compared to a 60Hz monitor or this monitor running at 60Hz (or 60fps), up to 2.75 times as much visual information is presented every second. This significantly enhances the ‘connected feel’, describing the precision and fluidity felt when interacting with the game world. The low input lag also aided this feeling. The combination of high refresh rate and frame rate also decreases perceived blur due to eye movement, demonstrated earlier with pursuit photographs. These photographs also demonstrated some significant weaknesses in pixel responsiveness, which significantly increased perceived blur. For transitions mainly involving light or medium and light shades, there was a bit of ‘powdery’ trailing which added something of a mask of perceived blur – nothing extreme. Where darker shades were involved, though, there were clear weaknesses. For very bright or highly saturated shades against medium backgrounds, such as when moving beside concrete or metal with brightly coloured paint on it, there were also significant weaknesses including ‘smeary’ trailing’. Similar to and in some cases more extensive than the sort of trailing demonstrated for the dark row of Test UFO earlier. Depending on the hue of the dark shades, various colours could leach out such as purple, blue and magenta as if wetting a page with water soluble ink on it.

Where dark and somewhat lighter shades combined, such as a bush with dark shadow detail alternating with the leaves or branches, a ‘flickering’ effect could also be observed. The lighter shades blended into the darker shades during movement and brightened up again when the movement ceased. For some isolated transitions (including with certain mixtures of medium and dark shades) we observed a bit of ‘halo’ trailing that’s slightly brighter than the background and ‘dirty’ trailing that’s darker than the background. This overshoot was sometimes slightly colourful in appearance, but we didn’t find it overly eye-catching or bothersome under SDR using our preferred ‘Faster’ setting. It was toned down using the ‘Fast’ setting – but this came at the expense of somewhat increased and more widespread ‘smeary’ trailing. And most of the colourful trailing observed under SDR was actually associated with significantly slower than optimal pixel responses. Under HDR there were some very clear and colourful flashes of overshoot using the ‘Faster’ setting which we found distracting. This was toned down or for some transitions eliminated using ‘Fast’, so we preferred ‘Faster’ for SDR and ‘Fast’ for HDR viewing. The likelihood of seeing very dark and brighter shades which are associated with the clearest weaknesses on this model are also increased under HDR, whilst the high brightness can make weaknesses more apparent. The section of the video review below highlights some of these weaknesses.

Similar observations were made on Shadow of the Tomb Raider. Plenty of these problematic ‘high contrast transitions’ are found on this title, so the weaknesses including ‘smeary’ trailing were rather widespread. Whilst these won’t be bothersome to everyone, they’re certainly quite noticeable with a somewhat weaker than average performance even for a VA model. We also observed video content at a range of refresh rates, including ~24 – 30fps content on platforms such as Netflix and 60fps YouTube content. For the 60fps content some fairly distinct weaknesses remained where darker shades were involved – less extensive ‘smeary’ trailing than observed at significantly higher frame rates, but ‘smeary’ in appearance nonetheless where various dark shades were involved. Nothing of particular note in the way of overshoot, however. Some weaknesses were apparent even for the ~24 – 30fps content where some dark shades were present. The trailing here was not ‘smeary’ in appearance as it stuck close to the object, but there was still a bit of a mask of additional perceived blur that ideally wouldn’t be there.

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VRR (Variable Refresh Rate) technology

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. 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 XG341C-2K supports FreeSync Premium Pro via DP and HDMI on compatible GPUs and systems. Note that HDR can be activated at the same time as FreeSync and ‘Local Dimming’ (SDR or HDR) can be used. You need to make sure ‘FreeSync Premium Pro’ is enabled in the ‘Display’ 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 Software’, click ‘Settings’ (cog icon towards top right) and click on ‘Display’. You should then ensure that the first slider is set to ‘Enabled’ as shown below. The top image shows the monitor connected by DP and the bottom image by HDMI. The setting is referred to as ‘Adaptive Sync Compatible’ via DP and ‘VRR’ via HDMI, although the exact wording may depend on the driver version and GPU you’re using.

The ViewSonic supports a variable refresh rate range of 48 – 165Hz. That means that if the game is running between 48fps and 165fps, the monitor will adjust its refresh rate to match. When the frame rate rises above 165fps, the monitor will stay at 165Hz 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 165fps, 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 >165fps). 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. If a game ran at 31fps, for example, the refresh rate would be 62Hz to help keep tearing and stuttering at bay. LFC often seemed to activate at slightly higher refresh rates, usually 55Hz (55fps) – this slightly different floor of operation makes little difference in practice. 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 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. 162fps) 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 go to ‘Setup Menu’ – ‘Information’ in the OSD, the current refresh rate of the monitor is listed. This updates in real time and will reflect the frame rate of the content, if the monitor is within the main VRR window. Finally, it’s worth noting 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 a range of game titles using AMD FreeSync and found the experience similar in all titles. Any issues which affect one title but not others would suggest a GPU driver issue or game issue rather than a monitor issue. To keep things simple we’ll just focus on Battlefield titles for this section. With these titles there is sufficient flexibility to allow the full VRR range of the monitor to be tested with our Radeon RX 580. Because this isn’t a particularly powerful GPU, it was very common to see dips below 165fps. Without a VRR technology like FreeSync, these dips cause frame and refresh rate mismatches which result in tearing (VSync off) or stuttering (VSync on). By keeping the frame and refresh rate synchronised, these issues are removed – which is very welcome if you’re sensitive to tearing or stuttering. The reduced frame rate still impacts the ‘connected feel’ and increases perceived blur, however. LFC worked as described earlier to keep tearing and stuttering at bay below ~55Hz. There was a momentary stuttering when it activated or deactivated, though this is something we always observe and not specific to this model. It was much less noticeable than traditional stuttering from frame and refresh rate mismatches and given the issues we explore later in this section, the least of your worries when using VRR on this model.

The monitor doesn’t suffer from extreme overshoot (for SDR, using our preferred ‘Faster’ setting) as refresh rate dips. It appears to use some degree of variable overdrive, or perhaps the acceleration wasn’t aggressive enough anyway to cause significant overshoot issues regardless. There was an increase in overshoot as refresh rate decreased, particularly into the double digits and below ~80fps – including some slightly bright ‘halo’ trailing, some ‘dirty’ trailing and some overshoot artifacts with an interlaced pattern to overshoot in places. We didn’t find this to be eye-catching and extreme overshoot. Even at these reduced refresh rates (frame rates), though, the more noticeable weaknesses stemmed from pixel response time weaknesses. They were somewhat less distinct given the decrease in pixel response requirements, but there was still definite ‘smeary’ trailing where darker shades were involved.

An issue which requires some discussion with VRR active on this model is ‘VRR flickering’. Monitors with particularly strong contrast (such as this one) are prone to flickering for some shades during heavy frame rate fluctuations. These are due to slight gamma changes at the lower end of the curve for certain refresh rate changes in a VRR environment and are not visible on models with relatively weak contrast. VA models like this are also particularly sensitive to the voltage changes that occur under VRR and particularly during heavy refresh rate fluctuation, which can cause flickering not just for darker shades but elsewhere as well. We observed significant and frequent flickering issues under VRR, even where the frame rate was stable and high. It was most intense when the frame rates and hence refresh rates were in the double digits, particularly below ~80fps (80Hz) and this was really rather distracting. The flickering was there even with mild to no real fluctuation in frame rate, including in the triple digits and near the maximum of the monitor. It was observable at any brightness level but became even more intense and distracting at high brightness, including with ‘Local Dimming’ active under SDR and HDR. Whilst we dislike tearing and stuttering, we found this flickering overbearing and preferred keeping VRR disabled for this reason.

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 or later 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 validated as G-SYNC compatible, which means they have been specifically tested by Nvidia and pass certain quality checks. With the XG341C-2K you can connect it up using either DisplayPort 1.4 or HDMI 2.1 to use ‘G-SYNC Compatible Mode’, with the latter technically making use of HDMI 2.1’s integrated VRR functionality rather than Adaptive-Sync. You need to make sure ‘FreeSync Premium Pro’ is switched on in the ‘Display’ section of the OSD to use the technology via DP as this acts as an Adaptive-Sync toggle on this monitor. 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 and press ‘OK’. If you’ve enabled ‘G-SYNC Compatible’ and it was previously disabled, the monitor should re-establish its connection with the system and the technology should now be active.



You will also see in the image above that it states: “Selected Display is not validated as G-SYNC Compatible.” This means Nvidia hasn’t specifically tested and validated the display, not that it won’t work. On our RTX 3090 the experience was very similar to what we described with FreeSync. With the technology getting rid of tearing and stuttering from what would otherwise be frame and refresh rate mismatches, within the VRR range. Similar VRR flickering behaviour was observed, with some clear issues there even with frame rates quite stable and particularly obnoxious for double-digit frame rates. The floor of operation again appeared to be 55Hz (55fps) most of the time, so 55 – 165Hz. Though 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 subtle momentary stuttering as the boundary was crossed, as we observed with our AMD GPU as well. Though accompanying flickering is going to be more noticeable than this. Our suggestions regarding use of VSync also apply, but you’re using Nvidia Control Panel rather than AMD 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’).



If you go to ‘Support’ – ‘Information’ in the OSD, the current refresh rate of the monitor is listed. This updates in real time and will reflect the frame rate of the content, if the monitor is within the main VRR window. And as with AMD FreeSync, HDR can be used at the same time as ‘G-SYNC Compatible’ and ‘Local Dimming’ (SDR or HDR) can be used.

HDMI 2.1 VRR

HDMI 2.1 includes Variable Refresh Rate (VRR) support as part of the specification. This is an integrated technology, which unlike FreeSync does not rely on VESA Adaptive-Sync to function. As such it be used by devices such as the PS5 that don’t support Adaptive-Sync. It can also be leveraged via ‘G-SYNC Compatible Mode’ on compatible Nvidia GPUs. You don’t need to have ‘FreeSync Premium Pro’ active in the OSD of the monitor to use this technology. That meant normal brightness adjustment was available with HDMI 2.1 VRR, whereas the setting was locked when using Adaptive-Sync (including ‘G-SYNC Compatible’ via DP). This aside and based on our testing of ‘G-SYNC Compatible Mode’ using HDMI 2.1 VRR, the experience was very similar to the Adaptive-Sync experience under SDR and HDR.

HDR (High Dynamic Range)

On an ideal monitor, HDR (High Dynamic Range) involves the simultaneous display of very deep dark shades and brilliant bright shades, with an excellent range of shades between these extremes. Including highly saturated shades with strong vibrancy and appropriately muted pastel shades. Ideally the monitor would offer per-pixel illumination (e.g. self-emissive displays such as OLED), or for LCDs a very large number of precisely controlled dimming zones would be used. An FALD (Full Array Local Dimming) solution such as Mini LED with a generous zone count, for example. This sort of solution would allow some regions of the screen to remain nice and deep for inky-looking dark shades, whilst at the same time others are very bright for brilliant light shades. Colour reproduction is also a key part of the HDR experience, 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. HDR10 is the most widely supported standard used in HDR games and movies and what is supported here.

For games and other full screen applications that support HDR, the XG341C-2K automatically switches to its HDR operating mode if an HDR signal is provided, as long as you have selected your preferred ‘HDR’ mode in the OSD. When we selected an ‘HDR’ mode in the OSD with an SDR signal and used our Nvidia GPU connected via DP, the image was completely messed up with intense oversaturation, shade crushing and clear inaccuracy. It also restricted the OSD options in the same way as HDR, explored shortly. When using HDMI 2.1 or with an AMD GPUs it provided the same experience as with ‘HDR’ set to ‘Off’ in the OSD and didn’t lock off any of the settings – so it could simply be left enabled. If you want to use ‘Local Dimming’ you must also remember to enable that. Then when switching back to SDR viewing may need to switch ‘HDR’ to ‘Off’ (as an Nvidia DP user) and disable ‘Local Dimming’ if you don’t wish to use it. Switching the ‘HDR’ setting in the OSD also seemed to reset our gamma to ‘2.2’ rather than the ‘2.0’ we selected. We found it far more convenient to avoid using Nvidia DP for this reason, but also feel ‘Local Dimming’ should be set separately for SDR and HDR. Also note that the ‘HDR’ and ‘Local Dimming’ settings are universal and can’t be tied to specific presets and therefore quickly changed just by changing preset. They can’t be assigned to the ‘Quick Access’ shortcut keys, either.

Some game titles will activate HDR correctly when the appropriate in-game setting is selected and the setting is enabled on the monitor. Others that support HDR will only run in HDR if ‘Use HDR’ is turned on in Windows, too. Related Windows HDR settings are found in the ‘Windows HD Color settings’ (Windows 10) or ‘HDR’ (Windows 11) section of ‘Display settings’ (right click the desktop). If you want to view HDR movie content, ensure ‘Stream HDR Video’ (Windows 10) or ‘Play streaming HDR video’ (Windows 11) is active. Also note that there’s an ‘HDR/SDR brightness balance’ (Windows 10) or ‘SDR content brightness’ (Windows 11) 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 that only makes changes for SDR content, and you lose contrast by adjusting it. Image balance is upset when viewing SDR content under HDR, as if gamma too high overall which makes some shades overly deep (or the opposite in the case of DP, with a generally foggy look) – colour accuracy also suffers. As usual, we’d recommend only activating HDR in Windows if you’re about to use an HDR application that specifically requires it.

For simplicity we’ll primarily focus on Shadow of the Tomb Raider in this section, though other games were tested and observed. This is a game we’ve tested extensively on a broad range of monitors under HDR know to have a good HDR implementation which is limited by the screen itself. It highlights strengths and weaknesses in a screen’s HDR capability appropriately. Although our testing focuses on HDR PC gaming using HDMI on an RTX 3090, similar observations were made when viewing HDR video content on the Netflix app. As with games, some HDR video content makes better use of HDR than others. There are some additional points to bear in mind if you wish to view such content. We also made observations using DP and with an AMD GPU as well. Using DP caused a strange ‘foggy’ appearance to many medium shades, independent of refresh rate, with a lack of depth to many scenes and elements within scenes. The sort of look you might expect under SDR if your gamma is set below ‘2.0’. This was a bit more pronounced on our Nvidia GPU compared to our AMD GPU, but noticed on both. Using HDMI on both GPUs (this would be used when viewing HDR content on an HDR compatible games console as well) yielded better results, with more appropriate depth. With ‘AMD FreeSync Premium Pro’ active in the OSD on our AMD GPU (either input), the representation was a bit different again, with more of a ‘contrasty’ look. There was an excessively deep look to some shades, whilst some medium-bright shades were over-brightened somewhat giving some blending together of highlight detail. Preferences for these various different ‘looks’ to HDR will vary, but we preferred the more natural-looking, accurate and ‘as expected’ HDR output delivered using HDMI (and without ‘AMD FreeSync Premium Pro’ active on the AMD side).

The screen includes three main HDR settings which were introduced earlier with respect to contrast and brightness; ‘DisplayHDR’, ‘CinematicHDR’ and ‘GameplayHDR’. If you’ve got ‘FreeSync Premium Pro’ active in the OSD then only ‘DisplayHDR’ can be selected. When we tested with our Nvidia GPU, the image did not change regardless of the mode selected. There may be some changes depending on your system or GPU – we only tested the ‘DisplayHDR’ setting with our AMD GPU. The only other difference was that, if ‘Local Dimming’ is disabled (removes any contrast advantage to HDR and we strongly advise against this), ‘brightness’ was adjustable using the ‘CinematicHDR’ and ‘GameplayHDR’ settings. Aside from that many settings are locked off under HDR including brightness, gamma, sharpness and colour channels. The monitor doesn’t apply clearly excessive sharpness under HDR like some models, however. The ‘Local Dimming’ settings (‘levels’) work in a similar way under HDR to what we described under SDR and shift things more towards dark biasing (‘Level 1’ in particular) or bright biasing (‘Level 4’ in particular). All settings are reactive and respond without obvious visual delay to changes in the image. Our preference under HDR is the same as it is under SDR here, so we set ‘Local Dimming’ to ‘Level 3’ and used the ‘DisplayHDR’ setting for the subjective assessment below. Again, personal preferences will vary and you should feel free to experiment with these settings and work out which you prefer.

The ViewSonic XG341C-2K is VESA DisplayHDR 1400 certified. This is the highest level of HDR certification provided by VESA for LCD models. Focusing first on the colour gamut, this certification level requires a minimum 95% DCI-P3 coverage. In this case the QD LEDs of the backlight provided 95% DCI-P3 with a fair bit of extension beyond DCI-P3 in the red to blue region – so a bit more encroachment onto Rec. 2020 than pure DCI-P3 would provide, but by no means full or near full Rec. 2020 coverage. This is a somewhat more generous gamut than we typically see on VA models, though falling short of some of the OLED models and also some Mini LED IPS models such as the ASUS PG32UQX, The gamut is shown in the representation below, where the red triangle shows the monitor’s colour gamut, the blue triangle DCI-P3 and green triangle sRGB.

Colour gamut 'Test Settings'