ASUS PA32UC

Interlace pattern artifacts

On some monitors faint interlace patterns can be seen during certain transitions, particularly noticeable where light shades (muzzle flashes, explosions etc.) briefly pop up on the screen. These are sometimes referred to as ‘inversions artifacts’. Alternatively, static interlace patterns can be seen with some shades appearing as faint horizontal bands of a slightly lighter and slightly darker version of the intended shade. We did not observe any such patterns, either dynamic or static, on this model.

Responsiveness

Input lag

A small utility called SMTT 2.0 was used alongside a sensitive camera to analyse the latency of the PA32UC, with over 30 repeat readings taken to maximise accuracy. Using this method, we calculated 23.67ms (just under 1.5 frames at 60Hz) of input lag. Note that there were no significant differences in this value when ‘Adaptive-Sync’ was set to ‘ON’ or ‘OFF’ in the OSD. We have no way to accurately measure input lag in the variable refresh rate and frame range environment under which FreeSync would be active, however. We don’t have the means to accurately measure the input lag in an HDR environment, either, but this value was not significantly different when ‘Dynamic Dimming’ was enabled vs. disabled. Note that the input lag value is influenced by the element you ‘see’ (pixel responsiveness) and the element you ‘feel’ (signal delay). It indicates a moderate signal delay, which some users would take issue with but others wouldn’t find bothersome.

Perceived blur (pursuit photography)

In our article on responsiveness, we explore the key concepts related to monitor responsiveness. One of the most important concepts explored here is ‘perceived blur’, contributed to in part by the pixel responsiveness of the monitor but generally in larger part by eye movement as you track motion on the screen. We discuss a photography method called ‘pursuit photography’, which uses a moving rather than static camera to capture snapshots of motion on a monitor in a way that reflects both elements of perceived blur. So not just pixel responsiveness but also eye movement.

The images below are pursuit photographs taken using the UFO Motion Test for ghosting, with the test running at 960 pixels per second. This is a 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. All background shade levels (dark, medium and light) were used with the monitor set to all its ‘Trace Free’ (TF) pixel overdrive settings; ‘0’, ‘20’,’ 40’, ‘60’, ‘80’ and ‘100’. The final image shows a 60Hz reference monitor, a Dell S2417DG, which gives an idea of how things should look where pixel responsiveness isn’t really a limiting factor.



The object itself appears quite broad and blurry, without sharp detail on the UFO body or within the cockpit. This indicates a moderate amount of perceived blur caused by eye (camera) movement – you can see this in the reference image as well, as you would expect. With ‘TF = 0’ there is also a reasonably bold trail behind the object, particularly for the dark and medium backgrounds. This is caused by slower than optimal pixel transitions. With ‘TF = 20’, this trailing is cut down a bit but is still significant. ‘TF = 40’ cuts it down further, whilst ‘TF = 60’ cuts it down again. At this point there is very little trailing remaining, just a faint ‘powdery’ trail. There is also a very small amount of overshoot (inverse ghosting) visible with the light background, whereby the pixel overdrive is slightly too aggressive and has caused the monitor to ‘overshoot’ the desired end shade for the transition. With ‘TF = 80’ the overshoot becomes more noticeable and is also present for the medium and to a lesser extent dark background. ‘TF = 100’ really ramps up the pixel overdrive so it’s far too aggressive. You can now see obvious bright and colourful overshoot trails. It is clear from this analysis that ‘TF = 60’ (the default level) is optimal in terms of providing a sensible level of pixel overdrive without noticeable consequences. – this was reflected in broader testing, beyond the transitions considered here. Note that with HDR active, you can’t adjust ‘TraceFree’. It behaves as if it is locked to its optimal and default value of ‘60’, however.

The image below shows pursuit photographs taken using the ‘Motion Sync’ strobe backlight setting. This is a confusing setting in that it has various levels of ‘refresh rate’. But as we’ve already confirmed with an oscilloscope earlier in the review, it causes the backlight to strobe at 120Hz in all cases. The monitor itself always remains at 60Hz, which is its native refresh rate and pretty much the highest refresh rate it will run at without frame skipping. The result of this is that all of these settings look similar. Slight differences are down to the images being taken at slightly different points of the strobe cycle. Perceived blur is arguably reduced as the main body has sharper details. But really, you’re just replacing a smooth ‘blurred’ appearance with a sharp fragmented one. Compare this with the reference shot, that shows the Dell S2417DG running at 120Hz with ULMB (Ultra Low Motion Blur) active. We found the ‘Motion Sync’ setting visually very uncomfortable and simply messy when gaming. This was compounded by the fact that white and near-white shades appeared with flashes of green and cyan. It didn’t matter which setting was used, the experience was much the same. For these reasons we will not be providing any further analysis on this feature. Note that you cannot use this setting with FreeSync active.

Note that we will not be including a section on overclocking, as the monitor displays artifacts or skips frames when set much above 60Hz at its native resolution or indeed lower resolutions such as Full HD.

Responsiveness in games and movies

On Battlefield 1 (BF1) there was a moderate degree of blur visible at all paces of movement, particularly when rapidly moving the mouse or driving in a vehicle. This was caused predominantly by eye movement, with most of the perceived blur tied to the 60Hz refresh rate of the display and its ‘sample and hold’ nature. There were some minor weaknesses in pixel responsiveness here and there, but nothing particularly ‘in your face’. There was a bit of ‘powdery’ trailing in places due to slower than optimal pixel transitions. Where very light shades were involved in the transition (such as white) you could see this most clearly, with a slight trail which added to perceived blur. There was also a little bit of light overshoot in places. When moving against a tree with bright blue sky in the background, for example, there was a semi-transparent ‘snail slime’ type of overshoot trail. This was not bright or obvious shadowy dark overshoot as you see on some models, so as with the powdery trailing was not something we consider distracting. Most users are unlikely to be phased by this or even notice it at all.

Dirt Rally echoed these experiences, with the vast majority of perceived blur linked to eye movement and the 60Hz refresh rate. There were minor weaknesses such as powdery trailing and overshoot. Some of the most pronounced powdery trailing occurred when racing at night, with very light shades from light sources cast against darker backgrounds. Even here, though, things were quite constrained. There was no obvious eye-catching overshoot, either, and to us things looked fairly similar to what they would even on the fastest ‘response time issue free’ LCDs. We also observed our Blu-ray test titles. Fluidity here is limited by the ~24fps at which they run. But the monitor itself did not present any obvious weaknesses from either slower than optimal pixel responses or overshoot.

FreeSync – the technology and activating it

AMD FreeSync is a variable refresh rate technology, an AMD-specific alternative to Nvidia G-SYNC. The monitor dynamically adjusts its refresh rate so that it matches the frame rate being outputted by the GPU, where possible. 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 Club3D Radeon R9 290 royalAce 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 PA32UC supports FreeSync via DP 1.2a (‘DP 1.2a+’) and Thunderbolt on compatible GPUs. If fully installed, AMD drivers feature Radeon Settings, which makes activation of the technology very simple and something that usually occurs automatically. Make sure you set ‘Adaptive-Sync’ to ‘ON’ in the ‘System Setup’ section of the OSD and you should be good to go. To make sure the GPU driver is setup correctly to use FreeSync, open ‘AMD Radeon Settings’ and click on ‘Display’. You should then ensure that the first slider, ‘AMD FreeSync’, is set to ‘On’. If you hover over this, it will also report the variable refresh rate display supported by the display. Note that the image below is for a different monitor and is just used as an example here.



The ASUS supports a variable refresh rate range of 40 – 60Hz. That means that if the game is running between 40fps and 60fps, the monitor will adjust its refresh rate to match. When the frame rate rises above 60fps, the monitor will stay at 60Hz 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 60fps, 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 >60fps). LFC (Low Frame Rate Compensation) is not supported by this monitor, as that requires the upper limit (ceiling) to be at least 2x the lower limit (floor) of FreeSync operation. FreeSync is therefore deactivated if the frame rate falls below 40fps, with the monitor then respecting your choice of VSync and presenting you with either stuttering (VSync on) or juddering and tearing (VSync off).

VSync is configured in the ‘Gaming’ section of ‘Radeon Settings’, where it is referred to as ‘Wait for Vertical Refresh’. You can either configure this globally under ‘Global Settings’ or for each game individually. 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. The fourth and final option, ‘Enhanced Sync’, is a relatively new addition to the driver. 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 than a monitor feature.



Note that the top right of the OSD displays the current refresh rate of the display. This updates in real-time (or close enough) to reflect changes in the frame rate, within the FreeSync Window (40 – 60fps). With FreeSync active you’ll see this constantly changing along with frame rate rather than just displaying ‘60Hz’ or whatever static refresh rate you had selected. This information is also contained in the ‘System Setup’ section of the OSD, under ‘Information’. Finally, it’s worth remembering 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.

FreeSync – the experience

As usual we tested a broad range of game titles using FreeSync on the monitor and found the experience much the same on each. For this reason, we won’t be talking about experiences on a broad range of titles, we’ll instead be focusing on a single title as an example. For a bit of variety and you’ll be quite sick of hearing about BF1 by this point in the review, we’ll instead be using Star Wars: Battlefront II for this section. Even at fairly low settings, some dips below 60fps are inevitable on this title using our Radeon R9 290. With FreeSync disabled, even if the frame rate drops just 1fps below to 59fps, the tearing and juddering (VSync off) or stuttering (VSync on) is obvious. That is, obvious to us, as individual sensitivity to these things does vary – but they’re relatively noticeable at these sorts of frame rates (vs. triple digit frame rates on high refresh rate monitors). As the frame rate dropped further, closer to 50fps, we noticed extra perceived blur and a worse ‘connected feel’ compared to 60fps. This wasn’t what we’d call a dramatic difference, though, and we were much happier to game at that sort of framerate with FreeSync enabled vs. disabled.

If we increased the graphics settings a bit, we experienced frequent drops to even lower frame rates. As things dropped closer to the 40fps (40Hz) floor of operation for FreeSync on the PA32UC, the ‘connected feel’ was significantly worse and perceived blur significantly higher compared to ~60fps. It’s also common to see more pronounced overshoot on FreeSync monitors, as the refresh rate drops without stuttering or tearing to help mask anything. G-SYNC monitors are specifically tuned to a broad range of refresh rates, where possible, so that the pixel responsiveness slackens off (and overshoot is less likely) at lower frame rates. You don’t need the same level of pixel responsiveness as you do at higher frame rates, so you might as well slow things down and reduce potential overshoot. With that said, the overshoot was only a little more pronounced as frame rate dropped below 60fps and as low as 40fps. We never found it distracting or particularly eye-catching, which is more than can be said for some FreeSync models. This is perhaps not surprising given that the FreeSync range is relatively limited here, with just 20Hz of range.

As noted earlier, the technology disables below 40fps (40Hz) and LFC is not supported. It would have been nice to have a FreeSync range that is a bit broader, with a lower floor. For gaming we don’t feel it’s a huge issue, as from our perspective such low frame rates are always a sub-par experience regardless of FreeSync being active or not. It is quite nice having those lower refresh rates for the support of low frame rate movie content, though. For example 30fps or even 24fps content can run at the correct frame rate or a multiple of it if a FreeSync monitor supports LFC. This reduces juddering, which some users appreciate, even if the fluidity remains limited by the low frame rate.

HDR (High Dynamic Range) and ‘Dynamic Dimming’

When it comes to displays, HDR (High Dynamic Range) describes the ability to distinctly display very deep dark shades and very bright light shades simultaneously. It is also necessary for a display to be able to display a large variety of shades in between, from weakly saturated to very heavily saturated shades. To achieve this, it would be attractive for a monitor to have hundreds if not more dimming zones on the backlight – something referred to as FALD (Full Array Local Dimming). In an ideal world it would be able to control the brightness of each pixel individually (OLED technology, for example). This capability would allow the monitor to correctly display intricate mixtures of bright and dark content. Some sections of the screen could display dark content with suitably low brightness luminance, whilst other sections of the screen display brighter shades with brilliant luminance. When it comes to colour reproduction on an HDR monitor, the ultimate goal is coverage of a huge colour gamut; 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, it is required that the display offers (at least) 10-bits per channel for colour processing, giving it the precision required to appropriately map shades for HDR content.

A lot of displays out there claim to offer ‘HDR’ capability, but when you look at the specifications and test them out it becomes clear that they lack a lot or in some cases all of the capabilities outlined above. The Dell U2518D is a good example of this – it’s a perfectly decent monitor for SDR, but its HDR capabilities aren’t anything to shout about (unless in a cursive way). To help bring some clarity to the situation, VESA offer a certification programme called ‘DisplayHDR’ which broadly categorises the overall HDR capabilities of a display. You can read more about this on the DisplayHDR website. For the PA32UC, ASUS doesn’t specify adherence to any particular DisplayHDR standard at time of writing. That may simply be because it isn’t certified as it seems to tick the necessary boxes for ‘DisplayHDR 1000’ on paper. It fully complies with the ‘HDR10’ standard favoured for PC usage and also reaches the ‘UltraHD Premium’ standard set out by the UHD Alliance (we know – all of these ‘standards’ are confusing). It supports true 10-bit colour, has a specified 1000 cd/m² maximum luminance and has a colour gamut of 95% DCI-P3. Furthermore, it uses a FALD (Full Array Local Dimming) backlight solution with 384 dimming zones. ASUS refers to this as ‘Dynamically Local Dimming’ technology and state that it achieves 1 µs operation. This compares to a ‘normal’ monitor that simply has the backlight all controlled as one single Backlight Unit (BLU). The little graphic below demonstrates FALD backlight arrangement. Note that the dimming zones are closer together and more numerous in reality. As explored earlier, you can enable or disable this feature in the OSD (‘System Setup’ – ‘Dynamic Dimming’) regardless of whether you’re viewing HDR or SDR (Standard Dynamic Range) content.

Just using the monitor for normal SDR content, we had mixed thoughts about the ‘Dynamic Dimming’ feature. On the desktop we found that some elements looked a bit unbalanced in terms of luminance. The monitor was clearly able to display reasonably large areas of individual shade at appropriate brightness and generally displayed very dark and very light shades (such as black and white) nicely. Where there were more intricate mixtures of shade with plenty of dark shades in the mix, the monitor often displayed things in a way that looked a bit dimmer than we’d like. The dimming zones tended to bias themselves towards the dark elements for the area of the image covering them, with the brighter and mid-tones looking somewhat dimmer than is ideal. This was most noticeable when browsing the internet and looking at pages with dark backgrounds. The surrounding light elements (text, icons, buttons etc.) had their luminance ‘dragged down’ by the neighbouring dark shades. This occurred even when brightness was raised as high as ‘100’, with the added drawback there being that some lighter content was uncomfortably bright.

Where bright shades moved between dimming zones, surrounded by much darker shades, the opposite problem occurred. There was a ‘halo’ effect, where the surrounding dimming zones were much dimmer than the ‘active’ zones that were displaying the bright shades. The claimed 1 microsecond operation of the dimming zones may be true for some brightness changes. But for the extremes explored here, we found the halos persisted after the moving light shade was no longer covering that particular dimming zone. The bright area faded out over the course of a second or so, rather than instantly disappearing. The halos also existed for mixed static content, for dimming zones covering mixed content that included very dark shades (most notably black). If neighbouring dimming zones were covered by the same very dark shade, they were noticeably dimmer than the dimming zones that contained that shade plus lighter shades. The video below illustrates these points and also runs through ‘Dynamic Dimming’ in other scenarios, including gaming and with HDR active. This is also explored in the paragraphs proceeding the video.

Whilst gaming or watching movies, we tended to find the ‘inconveniences’ described above easier to ignore. And, in fact, we found that the contrast advantage of using ‘Dynamic Dimming’ came into its own. You don’t tend to get big blocks of solid black that would conveniently cover an entire dimming zone when gaming, so dark colours (even black) don’t look as dark as the inky black bezel. Intricate mixtures of light and dark can’t be compensated for perfectly with the dimming zones being the size that they are, so you don’t get the same deep and inky look to shadow detailing. But things come a lot closer to that than without the ‘Dynamic Dimming’ feature active, especially when considering larger areas of darker shades. In dark rooms and shaded areas, where the darkest shades are dominant, the overall contrast is unmistakably enhanced. Here you get significantly deeper dark shades that really bring out subtle details and complement the excellent pixel density nicely. The black depth here surpasses what you’d see from any LCD with a regular backlight, even a high contrast VA panel. And because the backlight brightness for those zones is significantly reduced, the level of ‘AHVA’ glow is also reduced significantly. It’s still there to a degree, particularly if there are some lighter shades mixed in with the dark. Much like significantly reducing the backlight brightness on any IPS-type monitor with a normal backlight, though, the ‘glow’ becomes far more constrained. Bright elements such as fire, explosions and gunfire contrast nicely with these darker surroundings as well, with the dimming zones firing up as appropriate for such elements.

When it comes to HDR, the capabilities of the monitor are one (crucially important) thing. But you’re also at the mercy of the content itself, with some developers implementing HDR better than others. Some recent games consoles like the Sony PS4 Pro and Microsoft Xbox One X offer widespread support for HDR and can leverage the HDR capabilities of this monitor nicely. For PC games things are slowly getting there, but a bit patchy in places. Our observations below are based on PC titles which leverage the full HDR capability of the monitor – we’re not saying they’re perfect implementations, but they show off the technology well and will give a good idea of what to expect as both a PC user or HDR console user. Hitman is an example of a game that puts HDR to good use. Using ‘HDR 1’, we found that dark scenes maintained a good atmosphere (in a moderately well-lit room). The scenarios involving the Paris mansion at night, for example, had plenty of dark and shaded areas that were displayed nicely. Bright elements such as camera flashes, incandescent bulbs and the moon stood out very well. Mid-tones looked a bit faded in some respects, probably because the luminance was more constrained than ideal – especially if they’re shared by dimming zones covering a lot of dark shades as well. This is something we’ll explore in more detail using Battlefield 1 as an example shortly. ‘HDR 2’ made these bright elements stand out with an almost blinding brilliance and also made some of the mixed shades appear more saturated and lively (but not excessively so). Because the dark areas aren’t just solid masses of black, though, and the brighter shades are given higher backlight intensity in ‘HDR 2’, the overall luminance for the dark shades was raised. They looked less bold, deep and impressive even when viewed in a moderately well-lit room. The image below in no way represents what the monitor looks like first-hand with HDR active, but sets the scene in Hitman that we will describe below.



With HDR disabled, the moon (towards the top right) appears as a giant glowing mass that blends in with the illuminated area around it. With HDR active, the moon itself is distinct and the glow is far more natural and progressive. This is one of the advantages of the more accurate shade display supported by HDR and the 10-bit precision supported by both HDR10 content (such as this game) and the PA32UC. The other noticeable difference (with ‘HDR 1’) is that night actually looks more like night with HDR enabled, even if ‘Local Dimming’ is enabled under SDR. In the scene above, the bushes to the left and the carpeted area towards the bottom have distinct details with HDR off. With HDR on, these areas appear deeper and things look more ‘night-like’ and atmospheric. That is quite typical of the striking and high-contrast look developers usually go for when working with the HDR pipeline. On the flip-side, the fact that they are intricate mixtures of dark and lighter shades means that they are not displayed perfectly without the use of per-pixel lighting on a monitor. The level of detail is lower than it should be as the dark areas would ideally be deeper and darker than they are, with the lighter elements standing out a bit better. Without per-pixel lighting or tiny dimming zones it’s not possible to achieve that; the precision in illumination simply isn’t there. As we observed with the ‘Dynamic Dimming’ feature alone active, ‘AHVA glow’ (‘IPS glow’) is reduced in scenes like this. If you observe the image above, though, you’ll note that the upper left corner and bottom right corner of the screen do exhibit some of this ‘glow’; it’s not eliminated completely. The edge is taken off it such that viewing in a moderately well-lit room makes it unnoticeable. But because mixed (even if mostly dark) content is being displayed, the backlight dimming zones can’t just dim to super-low levels.

We’d now like to switch out attention to Battlefield 1 (BF1). This title also puts HDR to good use and is a title we have observed on multiple HDR-capable monitors and indeed feature in the video above. As with Hitman, there were compromises to both ‘HDR 1’ and ‘HDR 2’. With ‘HDR 1’, the dark areas appeared deeper, making such scenes far more atmospheric. As observed with ‘Dynamic Dimming’ alone, there were halos around some very bright shades surrounded by dark content. Because HDR unlocked potentially higher luminance for the bright shades, whilst keeping dark shades potentially rather deep, the halo effect was somewhat more pronounced. This was particularly noticeable for HUD elements such as the crosshair, map and ammo/health status. We actually preferred disabling the HUD for single player immersion when using HDR. ‘HDR 2’ made these light elements extremely bright and caused the very dark shades surrounding them to become flooded. For those who like to abuse their eyeballs with super-bright shades, don’t care so much about the ‘dark atmosphere’ or are gaming in quite a bright room this could be quite appealing. But we generally found ‘HDR 1’ preferable due to the better representation of dark shaded areas. As we mentioned with Hitman, medium-bright shades tended to look duller than with HDR disabled. These sorts of shades appear prominently on daytime maps. The ‘duller’ look is partly because ‘HDR 1’ limits the luminance somewhat and favours dark areas. Depending on room lighting, sensitivity (and once you let your eyes adjust) it isn’t so bad really. It’s also because HDR targets DCI-P3 (shown below with red triangle, monitor running DCI-P3 emulation mode) as the near-term target rather than being confined to ~sRGB (green triangle). And with monitors with proper HDR capability, like the PA32UC, developers are able to map shades with greater precision to this gamut due to 10-bit colour support and appropriate DCI-P3 coverage. Rather than shades appearing over-saturated during to be effectively stretched out beyond their natural sRGB-confined values, they can be accurately mapped to the desired location on the gamut.

Colour gamut 'DCI-P3'

The green tones of vegetation tend to look more natural, whilst earthy browns have their red hue toned down to appear less like a Martian landscape. It works well for the gritty and dirty aesthetic that the developers are going for with this title. But they can still pump in some extra vibrancy where they want to. This makes elements such as fire, explosion and sparks stand out very nicely. The relatively high luminance of such elements under HDR really helps as well (especially ‘HDR 2’, where they’re particularly brilliant). What we would say is that we find ‘HDR 1’ and ‘HDR 2’ quite polarising as they both bring distinct advantages and disadvantages to bear. We would have preferred for the user to have more control over luminance levels or for there to be another HDR option some way between ‘HDR 1’ and ‘HDR 2’. In contrast, we found the ‘Dynamic Dimming’ feature on its own brought distinct advantages compared to having the feature disabled. Although the luminance was dragged down a bit in places (or up elsewhere) and therefore a per-pixel solution would be far superior, having the added atmospheric look to dark areas whilst brighter areas remained pretty punchy was an attractive thing. A final thing to be aware of is that the Windows 10 ‘Creator’s Update’ added a feature called ‘HDR and advanced colour’. Refer to the Dell U2518D HDR section for information about how to enable or disable this feature. Once most HDR content is detected, the monitor will put itself into its HDR mode and display a message on the screen. So you’d only need to enable this in Windows itself if you’re trying to run HDR content that the monitor isn’t detecting for itself or that requires the Windows setting to be enabled.

The ‘4K’ UHD experience

We’ve taken a look at the ‘4K’ UHD resolution as it applies to a ~27” screen in our dedicated article on the topic. We’ve also looked more specifically at ~32” screens of this resolution In our BenQ BL3201PT/PH review. We won’t be repeating too much of what we’ve already covered in this article but will instead be reinforcing the main message. In our experience the ~32” screen size offers something of a ‘sweet spot’ for the ‘4K’ UHD resolution of 3840 x 2160 pixels. We say this because we find the combination offers excellent text clarity and readability even without scaling being used to make things larger (at the expense of ‘real-estate’). Mileage may vary in that respect, as it comes down to individual preferences and eyesight. We also feel that the pixel density is sufficient to bring about a level of detail and clarity that is distinctly’ in its appearance; with smaller screens and tighter pixel densities offering less of an improvement than coming from lower pixel densities to this screen. In terms of useful real-estate, whether reading a single document or multi-tasking (as below), the screen really delivers.

As noted in the previous paragraph, we find the pixel density of this screen attractive as well. The UHD resolution on a 32” screen provides a pixel density of 139.87 PPI (Pixels Per Inch). This takes things a step beyond 27” WQHD (2560 x 1440) models, which still offer a nice pixel density and overall experience but not at the same level as this. With a pixel density of 108.79 PPI, the 27” WQHD models offer a very similar pixel density to the ~40” UHD models. Again, this is a nice pixel density especially when spread across such a large screen, but we still feel this is a real step up and more noticeable than the steps up beyond that (27” or smaller UHD models, for example). Even if you have your game settings set to low values to conserve precious graphical horsepower, the resolution itself brings a certain sharpness and clarity that other resolutions simply can’t match. Once you bump the graphics settings up and add in higher resolution textures and particle effects, the screen really starts to shine. Especially on titles or elements within titles that really make use of the high resolution. In the case of our GTX 1070, though, it starts to struggle if graphics settings are increased all the way up on most titles. The smaller pixels and step up in clarity does at least reduce the need for anti-aliasing compared to screens with lower pixel densities, so you can usually get away with dialling that back a bit. The images below in no way represent how the screen looks when using it first hand and are limited by the camera and your own screen. Nonetheless, use them to fire up your imagination and ponder the beautiful sights that can grace users of the PA32UC first-hand.

Interpolation and upscaling

The 3840 x 2160 (‘4K’ UHD) resolution requires a fair bit of horsepower to run on graphically intensive applications. And in some cases (some games consoles or Blu-ray players, for example) it may not be supported at all. It may therefore be required to run the monitor at a lower resolution, such as 1920 x 1080 (‘1080p’ Full HD). For this and most resolutions there are two main options that can be selected in the OSD under ‘Image’ – ‘Aspect Control’; ‘Full’ and ‘1:1’. There is an additional ‘5:4’ setting specific to certain resolutions, as covered in the OSD. ‘Full’ causes the monitor to use an interpolation process to map the image with all of its pixels active, whilst ‘1:1’ is a direct pixel mapping feature. This means that only the pixels demanded from the source resolution will be used, with a black border filling up the remaining pixels. For 1920 x 1080, you get a 16” diagonal image surrounded by a large black border. If you wish to use the monitor’s interpolation process (‘Full’ setting) you need to make sure that the GPU doesn’t take over scaling duties. For AMD GPU users this is automatically handled by the monitor when gaming, by default. Nvidia users should open the Nvidia Control Panel and navigate to ‘Display – Adjust desktop size and position’. They should ensure that ‘No Scaling’ is selected and ‘Perform scaling on:’ is set to ‘Display’ as shown below.

The interpolation process used by the monitor via either HDMI or DP is excellent. There is only a relatively minor degree of softening when comparing the Full HD resolution on the PA32UC vs. a native Full HD screen of similar size. The overall detail in textures and definition of edges is quite similar to the native display. The same can be said for running other non-native resolutions, such as 2560 x 1440 (WQHD) – the degree of softening and detail loss is significantly lower than on many UHD monitors using interpolation. The flexibility you get to increase sharpness, should you wish to, will also be useful for some users – with both a ‘Sharpness’ and ‘Vivid Pixel’ setting offering some flexibility there.

As usual, If you’re running the monitor at 3840 x 2160 and viewing lower resolution 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 monitor of that resolution, but it’s not extreme and shouldn’t bother most users.

Conclusion

The ASUS PA32UC is an exciting and feature-packed monitor. To help settle users into the thought of having such an expensive monitor on their desk, it’s also important that it looks and feels like a premium product. In that respect, we feel ASUS did a good job. The monitor has a reassuring weighty metallic construction and good smoothness to its ergonomic adjustments (particularly height adjustment). As a member of the ProArt series, colour accuracy is a key focus with this model. The monitor includes a range of colour space emulation modes amongst its ‘Splendid’ presets that adjust colour gamut and various other attributes accordingly. Whilst they do have some utility, they were quite hit and miss with respect to gamma, white point and the gamut itself. For the highest levels of colour accuracy, a full calibration and frequent re-calibration is recommended, regardless of how good the presets of the monitor may or may not be. The hardware calibration capabilities of this model afforded good flexibility in that department, although the software itself was at times headache-inducing. With a bit of perseverance and numerous caffeinated beverages, we were able to achieve pleasing results.

The static contrast performance was largely on-par with our expectations, just a little short of the specified 1000:1 but not worryingly so. Although the testing conditions were somewhat artificial, as they have to be for controlled testing to take place, the monitor had its contrast greatly enhanced by its FALD (Full Array Local Dimming) solution. The 384 dimming zones of the backlight allowed the screen to simultaneously display good deep blacks and very bright whites – and hence, provided strong contrast ratios. Enabling HDR took this to another level and alongside very low black points, we recorded literally brilliant brightness that even slightly exceeded the specified 1000 cd/m². In the real world scenes are a lot more complex than just patches of pure black and white. And as we fully expected, there were drawbacks to having ‘just’ 384 dimming zones rather than per-pixel illumination (think OLED etc.) With ‘Dynamic Dimming’ active on the desktop, we found that the luminance of mid-tones sometimes got dragged down by adjacent very dark shades – the dimming zones were dimmer than ideal for the mid-tones, in order to display decent black depth. The monitor couldn’t compensate for intricate mixtures of light and dark in the same way a per-pixel solution could, either, as there just isn’t that level of precision available. Very light shades surrounded by very dark shades also produces ‘halos’ of light. These halos did not instantly disappear if the light shade was moved, either, and seemed to fade out instead.

In more dynamic environments such as gaming and watching movies, we didn’t really find these drawbacks noticeable. What we did notice is that dark scenes appeared far more atmospheric, with significantly reduced ‘AHVA glow’ and superior black depth. The dimming zones covering the very dark areas were able to dim effectively whilst dimming zones showing the main action (‘the bright stuff’) could stay pretty bright. This experience was unlike what you’d typically see from an IPS-type panel and in many respects outclasses what you’d see on a typical VA model as well. HDR added an extra layer of brilliance to the bright shades, with ‘HDR 1’ allowing for very high brightness that was very eye-catching indeed. Meanwhile, deep and dark shades remained ‘atmospheric’ in their depth – especially as HDR content tends to be created to really show off these extremes of contrast and have some really deep, dark shades. Mid-tones got dragged down a bit so that they could look a little less lively in places than we’d like, something more noticeable than with just ‘Dynamic Dimming’ enabled. ‘HDR 2’, meanwhile, gave truly retina-scorching brilliance to bright shades. But the black levels were lifted up too high by the higher luminance levels. Both HDR settings, with the more extreme contrast, also made ‘halos’ more noticeable where very bright content was surrounded by much darker content. We also disliked the inflexibility, with ‘HDR 1’ and ‘HDR 2’ being quite extreme in their differences and there not being the ability to tweak to a level between them both. Despite the imperfections, we did enjoy using ‘HDR 1’ in particular and found this to be the best monitor HDR implementation we’ve come across so far. Thanks in large part to the 384 dimming zones of the backlight, but also due to the very generous DCI-P3 coverage (as targeted by HDR10 content in the near-term) and 10-bit colour precision.

When it came to responsiveness, the monitor put in a capable performance in terms of pixel responsiveness. There were only mild weaknesses using the optimal ‘TraceFree’ setting, with the refresh rate being more of a limiting factor for those who enjoy greater visual fluidity. The input lag was moderately high, which may bother some users but not perturb others. We should also give a (dis)honourable mention to the ‘MotionSync’ strobe backlight setting, which caused the backlight to strobe at 120Hz regardless of the setting selected. We found this uncomfortable and whilst it could be argued it reduced perceived blur, the obvious object repetitions (splitting up of the trailing into multiple instances) really limited its effectiveness. The monitor also supports FreeSync, and that worked much as we’d hoped it would. The variable refresh rate range wasn’t astonishing, but within that range things worked well on the monitor with tearing and stuttering kept at bay. Without obnoxious levels of overshoot creeping in at the lower end. We should also finish by mentioning the resolution and screen size, which we feel is something of an optimal combination in terms of clarity and useful on-screen real-estate. When coupled with the other attractive features of the monitor, it is fair to say there is a lot to like about the experience. Then again, it’s not a cheap product and there are imperfections – so that could leave a sour taste in some people’s mouths.

The bottom line; a very capable monitor for both work and play, with some well-implemented features – but some quirks here and there.