Acer X35

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 observed static interlace patterns on rare occasions, when certain static images were displayed on the screen. One of the desktop backgrounds in our rotation, a mountain landscape, caused obvious static interlacing on the desktop background, taskbar and UI elements (vertical striping). The background itself is displayed on the monitor in the first image below, whilst the second image shows a zoomed-in section showing some icons and an area of background exhibiting the effect. It’s extremely difficult to capture on camera and this only gives a very rough idea of the vertical interlacing. This occurred regardless of the refresh rate selected. We observed the same sort of thing in Microsoft Word with 4 pages spread across the screen.

We noticed some slight dynamic interlace patterns in places as well, particularly under HDR, although for the most part these would be too faint for most users to notice or find bothersome. More noticeable was some obvious flickering and strong interlace pattern artifacts (thick ‘dancing lines’ with textures breaking up into a heavily interlaced pattern). This is likely an inversion artifact issue related to imperfect voltage regulation on the monitor. It occurred if the monitor was running beyond ~80Hz when certain textures were displayed. It wasn’t particularly widespread in general, although BFV seemed to have various scenes which caused the issue in a particularly obvious way. It was very rare on Shadow of the Tomb Raider and Mass Effect Andromeda, although there were some isolated instances on those titles. And there were some notable instances on Fallout 76, particularly during foggy weather. It is particularly noticeable if the refresh rate is fluctuating, so with G-SYNC active and the frame rate between 80 – 200fps. It doesn’t matter what static refresh rate is selected (except 60Hz, of course). Disabling ‘Over Drive’ rather than using ‘Normal’ or ‘Extreme’ fixes this issue, but obviously that’s an unattractive solution. This section of video highlights the issue and discusses the conditions under which it occurs.

As noted in the video we’ve been in communication with Acer regarding the obvious flickering and heavy interlace pattern artifact issue. Nvidia were also made aware of the issue. This issue has been resolved with new firmware.

Responsiveness

Input lag

A small utility called SMTT 2.0 was used alongside a sensitive camera to analyse the latency of the Acer X35, with over 30 repeat readings taken to maximise accuracy. Using this method, we calculated 4.91ms (~1 frame at 200Hz) of input lag. Note that this measurement reflects both the element of input lag you ‘see’ (pixel responsiveness) and the element you ‘feel’ (signal delay). It indicates a low signal delay which shouldn’t bother most users. Note that we do not have the means to accurately measure input lag in an HDR environment or with G-SYNC active in a variable refresh rate and frame rate environment.

Perceived blur (pursuit photography)

Our article on monitor responsiveness covers key concepts surrounding the topic. A key concept explored there is the notion of ‘perceived blur’. This is contributed to by both the movement of your eyes as you track motion on the screen and also the pixel responses of the monitor. The former is the key source of perceived blur on modern monitors, although the latter is also important. We also introduce a photography technique called ‘pursuit photography’, which uses a moving camera to capture motion on a monitor in a way that reflects both the pixel responsiveness and eye (camera) movement. Static photographs or videos, on the other hand, only represent the pixel response element 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 for capturing such photographs and highlights both elements of perceived blur nicely. The UFOs move across the screen from left to right at a frame rate matching the refresh rate of the display. The monitor was tested at 60Hz (directly below), 144Hz and 200Hz using all three ‘Over Drive’ settings; ‘Off’, ‘Normal’ and ‘Extreme’. Note that the monitor can also be set to 100Hz, 120Hz and 180Hz with perceived blur being some way between the respective values we’ve tested. All rows of the UFO Motion Test were used, highlighting a range of pixel transitions between various shades. The two final columns show two reference screens for comparison, where possible. The Acer Z35, which is the original 200Hz VA model from the company. And the ViewSonic XG240R, which is a very fast TN model that shows how things look where pixel responses are very rapid and not really a limiting factor. Both reference screens are using what we consider to be their optimal pixel response time settings.



At 60Hz, shown above, the UFOs appear relatively soft and unfocused without clear internal detailing. This reflects a moderate degree of perceived blur attributed to eye (camera) movement. There are also various amounts of trailing behind the UFOs due to weaknesses in pixel responsiveness. With ‘Over Drive’ set to ‘Off’ there is a fairly bold but short trail behind for the medium background (middle row), bolder and more extended for the dark background (bottom row). The light background (bottom row) shows no clear weaknesses in pixel responsiveness. The ‘Normal’ setting doesn’t really have much effect at 60Hz, for the transitions shown here, whereas the ‘Extreme’ setting introduces some overshoot (inverse ghosting). You can see some ‘dirty trailing’ (dark shadow-like trailing) behind the UFO for the dark background, with a bit of dirtying for the medium background. This occurred very mildly for the ‘Normal’ setting for the medium background as well, but in all cases this is subtle overshoot for this background. The Z35 reference shot shows more extensive ‘smeary’ trailing for the medium and dark backgrounds. Overall and considering a broader range of pixel transitions, we’d consider the ‘Normal’ setting optimal at 60Hz. The image below shows how things look with the refresh rate bumped up considerably to 144Hz.



At 144Hz, above, the UFOs appear significantly narrower and more sharply focused, with better internal detailing. This reflects a significant reduction in perceived blur due to eye movement. There are again varying degrees of trailing behind the UFOs. The ‘Off’ setting provides similar trailing behaviour to the same setting at 60Hz, but the pixel response demands have increased and perceived blur due to eye movement decreased due to the increased refresh rate and frame rate. You’re therefore left with trailing that is bolder and extends further behind the object. The ‘Normal’ setting ramps up the pixel overdrive so it’s more effective at this increased refresh rate. Some ‘powdery’ trailing remains for the medium and dark background, extended more for the dark background – but it’s less bold and extensive than the ‘Off’ setting. It’s also significantly less bold, extensive and ‘smeary’ than the reference Z35 screen. There’s also a little overshoot introduced, with a bit of bright (‘halo’) trailing behind the legs for the medium background and some overshoot mixed in with the conventional trailing for both the dark and medium backgrounds (behind the UFO body). This is not as strong as on the Z35 reference. The ‘Extreme’ setting ramps up the pixel overdrive up considerably. Much of the conventional trailing is gone, but it is replaced with obvious overshoot – including colourful ‘halo’ trailing. It’s clear from this analysis that the ‘Normal’ setting is optimal. Below you can see how things look with the refresh rate boosted to 200Hz, using the internal ‘Over Clock’ feature of the monitor.



The UFO is more sharply focused again, with some more distinct internal detailing including for the segmentation on the UFO’s body. This reflects a further reduction in perceived blur due to eye movement. There are again varying degrees of trailing behind the object. The respective ‘Over Drive’ settings work in much the same way as at 144Hz. The ‘Normal’ setting is again optimal. There are weaknesses, particularly for the dark and to a lesser extent medium background. Due to the increased refresh rate and increased pixel response requirements this carries with it, the trailing is a bit more pronounced than at 144Hz. But the weaknesses in pixel responsiveness aren’t as noticeable as on the Z35 reference. The ‘Extreme’ setting gives particularly bright and eye-catching overshoot now. On VA models in particular the pixel response speeds vary greatly depending on the shades (grey levels) involved in the transitions. This is reflected in this testing, but it’s important to look at a much broader range of transitions (grey levels) than shown here. And that’s something we’ll assess subjectively using in-game examples.

Responsiveness in games and movies

On Battlefield V the monitor provided a fluid experience, where the frame rate kept pace with the 200Hz refresh rate. Compared to a 60Hz monitor (or this monitor running at 60Hz), you’re getting ~3.33 times as much visual information every second. And compared to a 144Hz monitor, you’re getting ~1.39 as much visual information. This gives a strong ‘connected feel’, which describes the precision and fluidity that is felt when interacting with the game world. The low input lag also aided this feeling, but even with low input lag you can’t replicate this same ‘connected feel’ on a model with significantly lower refresh rate. The overall perceived blur is also greatly reduced, as demonstrated earlier using Test UFO. Compared to 144Hz, the step up to 200Hz isn’t dramatic – it’s more of a slight edge in both of these key areas. It certainly isn’t as noticeable as the step up from 60Hz to 144Hz and given how difficult it is to maintain ~200fps at 3440 x 1440 most users should see anything beyond low to mid triple digit frame rates as a bonus rather than essential.

Another key attribute which affects perceived blur is pixel responsiveness. We’ll set the scene using various high refresh rate VA monitors we’ve tested over the years. The worst performers are the likes of the old Acer Z35 (the original 2560 x 1080 @200Hz UltraWide model), with relatively obvious and widespread ‘smeary’ trailing. And, particularly at higher refresh rates, a large amount of ugly and eye-catching overshoot. The best high refresh rate VA models for pixel responsiveness would be the likes of the AOC C24G1 set to its ‘Strong’ overdrive setting, or the LG 32GK850G using the ‘Faster’ response time setting and with G-SYNC active in the graphics driver. The LG is a curious model in that G-SYNC’s activation state in the graphics driver affects pixel responsiveness quite markedly, something which some other reviewers didn’t do when assessing pixel response performance. These models have some weaknesses in terms of ‘powdery’ trailing, but there isn’t too much ‘smeary’ trailing to speak of. There’s relatively strong overshoot, although nothing as ugly as on the old Z35. Some way above that, there’s quite a spread of models such as the AOC AG273QCX, LG 32GK850F and a bit towards the faster side the Samsung C27HG70 all using appropriate optimal overdrive settings. There are some standout weaknesses there, although many pixel transitions are fairly fast – more so on the Samsung.

We’d put the Acer X35 some way between the best performers and the aforementioned Samsung, which is certainly nothing to be sniffed at. Most pixel transitions were performed very quickly, putting the 200Hz refresh rate to good use and delivering good low levels of perceived blur. There are weaknesses for some transitions, however. There’s a bit of ‘light powdery’ trailing in places, particularly where light objects are set against medium shades in the background. Examples of this are fairly isolated and this degree of trailing has a reasonably mild effect on perceived blur. There’s also some overshoot in the form of both slightly bright ‘halo’ trails and dark ‘shadowy’ trailing. Sensitivity to this varies, but we didn’t find it bothersome or particularly widespread – it was less noticeable than on those ‘fast VA’ examples we gave earlier. Even adding many darker shades into the mix only provided some ‘powdery’ trailing for the most part, but not the sort of widespread ‘smeary’ trailing of some VA models. There were some transitions that exhibited more distinct weaknesses, usually where a mixture of medium-dark and dark shades were involved in the transition. There were instances of ‘heavy powdery’ trailing with a ‘smeary’ quality in places. For example, moving against a dark post with twilight sky in the background. Or with very light shades (white or near-white) against significantly darker backgrounds – such as white in-game icons against dimly lit interiors. There was also a bit of ‘break-up’ trailing whereby some of the colours contained within very dark objects, such as blue, appeared to leach out with a slightly colourful trailing. Like wetting a page with water soluble ink on it. Even these more pronounced trailing examples didn’t have the sort of extensive smeary quality of some VA models, though, and the slowest pixel transitions which caused the most noticeable issues weren’t particularly widespread. The section of the video review below gives some examples of the trailing behaviour and highlights the strengths of the monitor’s responsiveness.

Whilst we don’t consider ourselves competitive gamers, we still like to do well on games like Battlefield V. We didn’t feel this model significantly hampered our gaming performance on titles like this or that we’d perform significantly better on a high refresh rate model with universally fast pixel responses. This contrasts with many high refresh rate VA models, where there are weaknesses which are obvious or widespread enough to really undermine competitive gameplay or cause general frustration. Examples of screens with such weaknesses were given earlier. Even the Samsung C27HG70, which is far from the slowest VA offering, gives us this feeling of being somewhat held back competitively in a way we don’t really on the X35. We wouldn’t say it’s just the pixel responsiveness that gave a good feeling to competitive gameplay for us. But the combination of high refresh rate, decent pixel responsiveness, low input lag and enhanced FOV from the 21:9 aspect ratio all came into play. This is all very subjective and personal sensitivities vary, of course.

Given the extensive analysis above, we don’t really have much to add from our experiences on Shadow of the Tomb Raider. Naturally, this is a somewhat more laid-back adventure game where the competitive edge isn’t so important. Nonetheless, the high refresh rate and good overall pixel responsiveness gave a nice edge to our enjoyment on this title. High contrast scenes are naturally widespread on this title, so some of the weaknesses we observed on BFV applied here as well. A bit of overshoot in places and some clearly slower than optimal pixel transitions involving very dark shades. But these weaknesses were neither extreme nor particularly widespread in our view. Even when running about in dark caves, things looked distinctly unlike they do on most VA models. We also observed a range of movie and video content, of various frame rates, including ~24 – 30fps content and 50 – 60fps. There were no clear weaknesses for the lower frame rate content, whilst only some isolated weaknesses for the higher frame rate content. A bit of ‘powdery’ trailing and a very small amount of (rather faint) overshoot in places. We didn’t find these weaknesses distracting or even particularly easy to notice in general, not as ‘in your face’ as the weaknesses on some VA models. The frame rate was the main limit to fluidity for this content rather than there being clear and widespread weaknesses from the monitor’s pixel responses.

As an Amazon Associate I earn from qualifying purchases made using the below link. Where possible, you’ll be redirected to your nearest store. Further information on supporting our work.

G-SYNC – the technology and activating it

Nvidia G-SYNC is a variable refresh rate technology that can be activated when a compatible Nvidia GPU is connected to a compatible monitor (such as the Acer X35). Our article on the technology explores the principles behind the technology and its benefits, so we won’t be repeating too much of that. Essentially the technology allows the monitor to dynamically adjust its refresh rate to match, where possible, the frame rate outputted by the GPU. When the two are in sync it gets rid of the tearing (VSync off) and stuttering (VSync on) that occurs when the two are unsynchronised. An additional benefit for those who hate tearing and usually like to use VSync is a reduction in latency compared to ‘VSync on’ in the variable frame rate environment. As noted in the responsiveness section, though, we don’t have a way to accurately measure this.

This monitor supports G-SYNC via DP 1.4 (DisplayPort), once connected to a compatible Nvidia GPU such as the GTX 1080 Ti used in our test system. Once connected up, G-SYNC should be automatically configured and ready to use. There’s usually even a little notification icon in the system tray telling you that a G-SYNC compatible display is detected. To check everything is configured correctly, open Nvidia Control Panel and navigate to ‘Display – Set Up G-SYNC’. Ensure that the checkbox for ‘Enable G-SYNC’ is checked, then select your preferred operating mode. As the image below shows, this technology works in both ‘Full Screen’ and ‘Window’ modes, provided the correct option is selected for this. If the G-SYNC options seem to be missing from Nvidia Control Panel, this may be remedied by reconnecting the GPU or possibly connecting the monitor to a different DP output if there’s one available. If the options are still missing, reinstalling the GPU driver or updating this is recommended.

Enable G-SYNC

Next you should navigate to ‘Manage 3D settings’. Here there are a few settings of interest, the first of which is ‘Monitor Technology’. This should be set to ‘G-SYNC’ as shown below. Assuming this is all set up correctly, you should see ‘NVIDIA G-SYNC’ listed as ‘Mode’ in the ‘Information’ section of the OSD menu (press top menu button when in main menu). The refresh rate listed there just corresponds to the static refresh rate you’ve selected in Windows or your game (‘Max Refresh Rate’ as stated). You can also set ‘Refresh rate num’ to ‘On’ in the ‘OSD’ section of the OSD to display the current refresh rate. This will correspond to your content’s frame rate if G-SYNC is actively doing its thing.

Set Monitor Technology to G-SYNC

The second setting of interest is VSync, which can be set to one of the following; ‘On’, ‘Use the 3D application setting’, ‘Off’ or ‘Fast’ (GPU dependent). The Acer supports a variable refresh rate range of 30 – 200Hz, with the maximum value (ceiling) corresponding to the refresh rate you’ve selected for the monitor in Windows or your game. That means that if the game is running between 30fps and 200fps, the monitor will adjust its refresh rate to match. When the frame rate rises above 200fps, the monitor will stay at 200Hz and the GPU will respect your VSync setting in the graphics driver. If you select ‘On’, VSync activates if the frame rate exceeds the static refresh rate that you’ve selected (e.g. 200Hz / 200fps) and the usual VSync latency penalty applies. If you select ‘Off’ then the frame rate is free to rise in an unrestricted way, but the monitor will only go as high as 200Hz – tearing and juddering will ensue if the frame rate rises above this. The ‘Use the 3D application setting’ largely works as you’d expect, but the general recommendation is to set VSync in the graphics driver if you wish to use it as in-game implementations can interfere with the smooth operation of G-SYNC. Some users prefer to leave VSync disabled and use a frame rate limiter set several frames below the maximum supported (e.g. 196fps) instead, avoiding any VSync latency penalty at frame rates near the ceiling of operation or tearing from frame rates rising above the refresh rate.

The ‘Fast’ option is available on some newer GPUs, such as the GTX 1080 Ti used in our test system. This enables a technology called ‘Fast Sync’, which only applies above the refresh rate and frame rate ceiling (>200Hz / 200fps). Below this G-SYNC operates as normal, whereas above this a special version of VSync called ‘Fast Sync’ is activated. This is a GPU rather than monitor feature so isn’t something we will explain in detail, but it is designed to reduce tearing at frame rates well above the refresh rate of the monitor. If you’re interested in this technology, which may be the case if you play older or less graphically demanding games at very high frame rates, you should watch this section of a video by Tom Petersen.

Set VSync according to preferences

If the frame rate drops below the lowest refresh rate supported by the monitor (i.e. the G-SYNC floor of 30Hz / 30fps) then the monitor sets its refresh rate to a multiple of the frame rate. This occurs regardless of VSync setting. If for example the game ran at 18fps, the monitor would set itself to 36Hz. This keeps stuttering and tearing from non-even divisions of frame rate and refresh rate at bay. As we explore shortly, though, low frame rates are low frame rates regardless of the technology. So whilst it is always beneficial to have stuttering and tearing removed, it’s also beneficial to have an elevated frame rate where possible. It’s also worth remembering that G-SYNC can’t eliminate stuttering caused by other issues on the system or game environment such as insufficient RAM or network latency. Some game engines will also show stuttering (or ‘hitching’) for various other reasons which won’t be eliminated by the technology. Finally, note that G-SYNC can be used at the same time as HDR.

G-SYNC – the experience

We tested a range of game titles on this monitor using G-SYNC, with the technology working in much the same way across all titles. We’ll therefore be focusing on just one title in this section; Battlefield V. Achieving 200fps is no easy task on titles like this at 3440 x 1440, even with a fairly powerful GPU such as the Nvidia GTX 1080 Ti at the helm. There were frequent drops below this, which would ordinarily cause a frame rate and refresh rate mismatch where a variable refresh rate technology like G-SYNC is absent. Enabling VSync would give obvious (to us – sensitivity varies) stuttering whilst disabling VSync would give obvious (to us) tearing and a juddering effect, in such scenarios. With G-SYNC enabled there are no such mismatches and the refresh rate is dynamically adjusted to match the frame rate. This keeps things ticking over nicely, without such interruptions to the flow.

Even with G-SYNC active, reduced frame rates can be felt due to the decreased ‘connected feel’ and increase in perceived blur than ensues. The drops down to 144fps, as an example, reduce the ‘connected feel’ a little and slightly increase overall perceived blur. But the comparison with 200fps is not exactly dramatic. With graphics settings ramped up or more intense scenes, it’s common to see further drops, into the double digits. At the upper end of this (~100fps) the drop off in ‘connected feel’ and increase in perceived blur is significant compared to ~200fps – but the game is still quite playable. As things drop further, the drop-off in both areas becomes something of a nuisance. Much less of a nuisance than when it is coupled with tearing or stuttering from refresh rate mismatches, however. G-SYNC again did its thing to rid the experience of such unpleasantries.

In extreme situations, with absurdly high graphics settings (including hugely increased rendering resolution), dips below 30fps were observed. Although the monitor can’t refresh at below 30Hz, G-SYNC ensures that the monitor’s refresh rate sticks to an exact multiple of the frame rate. This did its thing to keep tearing and stuttering at bay and there was no obvious transition when it happened. However; the ‘connected feel’ and extreme level of ‘perceived blur’ makes playing at such frame rates very unpleasant anyway. An additional distraction that’s common to FreeSync monitors (those using Adaptive-Sync rather than a dedicated G-SYNC board) is ever-increasing overshoot levels as frame rate reduces. As a G-SYNC model, variable overdrive is used to slacken off the pixel overdrive impulse as appropriate as refresh rate reduces. This keeps overshoot levels in check, ensuring they don’t suddenly become burdensome just because your in-game frame rate has dropped.

SDR Variable Backlight

As explored in the contrast section earlier, the monitor has a 512-zone FALD (Full Array Local Dimming) backlight. This is active under HDR, but can also be used under SDR by setting ‘SDR Variable Backlight’ to ‘On’ in the ‘Picture’ section of the OSD. Without this setting active, the backlight is controlled as a single unit. With it active, the backlight is split into 512 independently controlled zones. This greatly enhances contrast, as demonstrated numerically earlier, allowing the monitor to display good bright light shades and good deep dark shades simultaneously. It also reduces ‘VA glow’ as backlight zones covering darker content can be dimmed very effectively. Whilst 512 dimming zones is certainly a decent number, it’s worth putting it into perspective. It’s still a very small number compared to the number of pixels on the monitor – nearly 5 million of them. Many scenes are an intricate mixture of light and dark, so a single dimming zone will need to display both very light and very dark shades at the same time. Because this isn’t possible, it will compromise by considering the average brightness of the content in that zone but often weighting things more towards the bright content. In effect some of the darker elements are lifted up and appear brighter than they should. If there is lots of dark content surrounding this, covering adjacent dimming zones, you’ll notice that this dark content appears significantly deeper than the dark content for the more brightly illuminated dimming zones. This creates a ‘halo’ effect near the bright content.

We found this ‘halo’ effect most noticeable when on the desktop and observing large areas of solid colour. The white mouse cursor moving around the screen could lift up the brightness of a dimming zone considerably as it passed over it, brightening up all shades contained there considerably compared to surrounding content. The reactivity was excellent using the ‘Gaming’ setting for ‘Backlight Response’, though. There wasn’t a slow fade of the dimming zone back to its darker state. Further good news is that the halo effect was much less readily observed when playing a game or watching movie content. It was certainly there in menu systems and suchlike with small bright elements or a light mouse cursor moving against darker solid backgrounds. But far more noticeable was the overall enhanced contrast that was evident with ‘SDR Variable Backlight’ enabled. There were much nicer distinctions for predominantly dark content, whilst brighter shade stood out very nicely. For extreme and sudden changes in luminance, such as a bright candle surrounded by darkness from a cave, a ‘halo’ was certainly visible. Although it was more subtle than the ‘halo’ effect observed on the 384-zone FALD ‘4K’ HDR models we’ve tested like the ASUS PG27UQ. And if it occurred near the periphery of the screen, you didn’t have to worry about ‘IPS glow’ being invited at the same time. The exception to this was when viewing the screen from a sharper angle – the ‘halo’ effect then become extremely pronounced. But from a normal viewing position, using ‘SDR Variable Backlight’ was very much a no-brainer for us when gaming or watching video content. This section of video shows this feature in action and runs through the pros and cons.

HDR (High Dynamic Range)

On an ideal monitor, HDR (High Dynamic Range) describes the ability to distinctly display very deep dark shades whilst simultaneously displaying very bright light shades. Plus an excellent array of shades between those extremes – including some highly saturated shades and much more muted shades. The monitor would ideally have individual illumination of each pixel or failing that a very large number of dimming zones. The use of a large number of dimming zones is referred to as FALD (Full Array Local Dimming) capability. With a great number of dimming zones, illumination can be controlled with excellent precision. Allowing some areas of the image to be very dim, with deep dark shades. Whilst other areas remain exceptionally bright, with strong luminance output and brilliant light shades. In addition to these strong contrast credentials, being able to display a huge range of colours is ideal. The ultimate goal with this in mind is coverage of a massive colour gamut known as Rec. 2020. A more achievable near-term aim is for a monitor to offer 90% DCI-P3 (a Digital Cinema Initiatives standard colour space). Finally, HDR makes use of 10-bit+ precision per channel, so it’s desirable for the monitor to support (at least) 10-bits per subpixel.

It is specifically the HDR10 pipeline which is currently used on monitors and the common standard supported most widely in games and other applications. For most games and other full screen applications that support HDR, the Acer X35 will automatically switch into its HDR operating mode. 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. In this case it simply acts as a digital brightness slider, so you lose but never gain contrast by adjusting it. Most users will find the image too bright for normal viewing when leaving this at the neutral position (‘50’), which also offers optimal contrast. The colours and overall image did at least look better balanced than many screens when you activate HDR and view SDR content. It appeared some way between SDR using the native gamut and with ‘SDR Colors sRGB’ active. Due to the brightness restrictions and inability to adjust that without loss of contrast, this won’t be a setting that you’ll want to use routinely when viewing SDR content. 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.

As a G-SYNC Ultimate monitor, the Acer X35 is VESA DisplayHDR 1000 certified. In many respects this is the highest level that VESA currently certifies for and it requires support for a number of attractive features for HDR. The monitor has a specified 90% DCI-P3 colour gamut, which matches the criteria for VESA DisplayHDR 1000 certification. From our measurements we have no reason to doubt this claim. Although our testing is focused on HDR PC gaming, our observations apply more broadly to HDR movie consumption and running HDR on compatible games consoles. The experience is shaped largely by the capabilities and limitations of the screen itself. We tested various game titles and observed a range of video content under HDR, but will focus our observations for this section on two titles; Battlefield V and Shadow of the Tomb Raider. We’ve tested these and similar titles (such as BF1) on a range of HDR-capable monitors, so we have a good range of references to compare with and know these titles offer good HDR implementations which separate weak and strong HDR monitors.

The monitors ~90% DCI-P3 colour gamut was put to good use on these titles, where developers target DCI-P3 rather than sRGB. Although we did not observe extreme oversaturation under SDR, there were some instances of slightly higher than intended saturation. Skin tones and woody tones showing too much red, for example. And some green hues appearing with yellow hues that were a bit stronger than intended, or simply appearing a bit too bright and vivid. Under HDR and the gamut being targeted appropriately, such elements appeared suitably muted and natural with these stronger than intended tints toned down. The game developers are also able to make shades that are intended to look vibrant look suitably eye-catching. A good example of this is licks of vivid oranges and yellows from flames, with saturation levels comfortably beyond the boundaries of sRGB. And some beautiful lively-looking deep purples, reds and golds of flowers and painted objects. The saturation levels weren’t as high here as on, for example, the ASUS PG27UQ. The colour gamut there covers more of the DCI-P3 colour space and colours are also a bit more consistent due to the panel type. But the overall representation of the shades here was pleasing under HDR. As a reminder, the colour gamut of the monitor (red triangle, below) offers good extension beyond sRGB (green triangle, below) and reaches fairly close to the DCI-P3 colour space targeted by game developers for HDR content.

Colour gamut 'Test Settings'