Samsung C27HG70

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 ‘pixel inversion 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 observed a faint ‘mesh’ effect during motion on the monitor, whereby some shades would appear with a faint grid of small polygons in the background. This was not something everyone would notice or find bothersome, especially if the screen is placed a reasonable distance from the viewer. We also observed faint static interlacing on some shades, particularly some oranges and reds. These bands were very faint, most users wouldn’t notice and some would struggle to see them even if they were pointed out; we’re just mentioning for completeness. Note that they occur regardless of FreeSync being active and are independent of refresh rate.

Responsiveness

Input lag

A small utility called SMTT 2.0 was used alongside a sensitive camera to analyse the latency of the C27HG70, with over 30 repeat readings taken to maximise accuracy. Using this method, we calculated 3.88ms (just over half a frame at 144Hz) of input lag. This value was recorded with ‘Low Input Lag’ set to ‘On’ in the OSD. The measured value was very similar when connected to a FreeSync-compatible GPU with FreeSync enabled in the OSD and was similar with the monitor set to 60Hz. Enabling FreeSync actually forces ‘Low Input Lag’ on, even though it’s greyed out. 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 enabling ‘Local Dimming’ alone had no significant effect on the measured value. Note that the input lag value is influenced by the element you ‘see’ (pixel responsiveness) and also the element you ‘feel’ (signal delay). It indicates a very low signal delay, which contributed to an excellent ‘connected feel’ as we explore shortly.

Perceived blur (pursuit photography)

In our article on responsiveness, we explore 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 60Hz. Only the ‘Standard’ response time setting was tested as the other settings are greyed out at 60Hz. 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.

You can see in the 60Hz images above that the object itself appears soft and poorly focussed, indicating significant perceived blur due to eye movement. This aspect is the same as he reference image, which shows an equally soft main image without crisp detail. The CHG70 exhibits noticeable overshoot (inverse ghosting) behind the object, visible as a bright and colourful trail that’s most pronounced on the dark and medium backgrounds. This is caused by excessive levels of pixel overdrive (grey to grey acceleration). The image below shows performance at 100Hz and 144Hz, with all ‘Response Time’ settings considered. The reference column includes a range of screens set up as noted; the Dell S2417DG, AOC AG251FG and Samsung C24FG70.

At 100Hz using the ‘Standard’ response time setting, the level of perceived blur due to eye movement is reduced compared to 60Hz. You can see that the object itself appears narrower and more focused. There is a degree of trailing behind this, strongest with the dark background, due to slower than optimal pixel response times. There is a bit of overshoot visible for the lightest background, but this is quite faint. The reference image from the S2417DG actually looks reasonably close to the comparable medium cyan background (middle row) for the C27HG70. The ‘Faster’ and ‘Fastest’ settings look very similar to one another. The image appears significantly sharper, reflecting a large and readily noticeable reduction in perceived blur. That is because these response time settings activate the ‘Impulsive Scanning’ strobe backlight mode, explored shortly. There is a fair bit of trailing behind, appearing as quite a bold repetition of the object that’s most noticeable for the dark and medium backgrounds. This is due again to slower than optimal pixel transitions; they’re not keeping up with the 100Hz strobing. The reference shot for the S2417DG uses ULMB, an alternative strobe backlight mode, which isn’t perfect either as it produces some overshoot. The details on the main object are a somewhat crisper on this reference shot due in part to superior pixel responsiveness.

At 144Hz with the ‘Standard’ setting, you can see a further sharpening of the image compared to ‘Standard’ at lower refresh rates. It also appears slightly narrower. This is, again, due to reduced perceived blur from reduced eye movement. The trailing behind the object is not bad for the light background, a bit bolder for the medium background (compared to 100Hz) and a fair bit bolder for the dark background. This may be partly due to the pixel response times slackening off a bit, but will be more heavily influenced by the fact the pixel responses simply aren’t keeping up with the responsiveness demands of the elevated frame rate and refresh rate. The ‘Faster’ and ‘Fastest’ settings are again very similar to one another –slight differences for the dark background are down to the camera, not picked up in this way by eye. The image appears a bit sharper with superior details compared to 100Hz with similar response time settings. The details aren’t as sharp as the ULMB reference shot, however. The trailing is fairly similar to under the ‘Standard’ setting, due to similar pixel response time weaknesses, with the fragmented nature associated with strobe backlight operation making the trailing for the dark background appear particularly pronounced.

Although not included in this analysis, we did make observations at other refresh rates. 120Hz offered similar performance to 144Hz in terms of pixel responsiveness, with the object itself appearing between 100Hz and 144Hz in terms of how focused it appeared. It is also interesting to compare 144Hz pixel response performance to the AOC AG322QCX, which uses a larger variant of the same panel. This wasn’t included in the reference images simply as we didn’t want to cram too much in there. However; performance on this Samsung appears mostly similar to the AOC using its ‘Weak’ response time setting. Except for the light background which appeared some way between the ‘Medium’ and ‘Strong’ settings of the AOC (which is good). This suggests that, overall, the AOC has slightly better tuned pixel overdrive under using its optimal ‘Medium’ setting. And it offers more flexibility than the Samsung does, with the Samsung offering only one ‘Response Time’ setting without activating the strobe backlight function. Nonetheless, these TestUFO shots only analyse a select range of pixel transitions – we make a much broader assessment below.

Responsiveness in games and movies

On Battlefield 1, at suitably high frame rates (the higher the better, up to 144fps), it was clear that this was a 144Hz monitor we were using. There are two main benefits, both of which this monitor encapsulated. Because the monitor is displaying up to 2.4 times as much information every second as a 60Hz monitor (60fps), interactions with the game world were more fluid. This was particularly noticeable when using the mouse, which aided precision and what we like to call the ‘connected feel’ when gaming. The other benefit of this high refresh rate and high frame rate is that the overall level of perceived blur was significantly reduced. Objects retained sharper focus and more detail as you move about in the game world, making it easier to track and engage enemies. For the most part the pixel transitions made good use of this refresh rate and were fast enough for an optimal or near-optimal performance. Some of the transitions that were quite common on this title (between various ‘medium’ shade brightness levels) did show some signs of weaknesses in the form of a bit of powdery trailing. This was fairly faint, but sufficient to slightly increase perceived blur particularly during rapid movement. There was also some overshoot here and there, with some semi-transparent (‘snail-slime’) trails; these were again faint, we did not observe any obvious bright or dirty-looking dark overshoot trailing.

As is always the case with VA panels, to varying extents, there were some notable weaknesses in pixel responsiveness. The most significant of which occurred where dark shades were involved in the transition, particularly where significantly lighter shades were present in the background. On this title these are most common on the darker maps but also occur in places on the brighter maps, for example in darker interiors or where there are dark metal objects case against a bright sky. On some titles such transitions are actually much more common (Mass Effect Andromeda being an example). You could see a more extended ‘smeary’ trailing in these instances. This was not as pronounced as we’ve seen on some VA models where might appear almost like smoke billowing off the object, but it is something some users would notice and be bothered by. There was also some ‘break-up trailing’ we observed, whereby dark shades would have subtle hints of certain colour such as red or blue that aren’t visible in the object itself. But which appeared to separate out from the object as a slightly colourful trail, a bit like wetting fountain pen ink on paper. These weaknesses would not be enough to distract or bother all users, it must be remembered. And the monitor still performs well at 144Hz in other respects and makes good use of the refresh rate. Overall we’d say it’s on par with the likes of the AOC AG322QCX and ASUS XG32VQ for some transitions, a bit slower for some and a bit faster for others. The tighter pixel density helps keep some of the trailing more contained and compact and thus less noticeable, however. The section of our video review below highlights some of the weaknesses in pixel responsiveness on the CHG70.

Given our fairly extensive observations above on BF1, we don’t have much to add with our experience on Dirt Rally. This title, again, had a good mixture of pixel transitions. And for the most part the 144Hz was beneficial at high frame rates in terms of connected feel (although less so in our case as we’re keyboard rookies on this game) and in terms of reducing perceived blur. The weaknesses highlighted on BF1 and TestUFO were present, particularly when driving at night. There was a bit of ‘powdery’ trailing in places and some of the ‘smeary’ plus ‘break-up’ trailing in others. Observing trees or hilltops at night with the somewhat brighter sky as a backdrop highlighted these weaknesses. And, depending on the tone of the sky (a slightly purple hue on some courses) there was a bit of overshoot present as well. Not really bright and eye-catching, but still there. When focusing on racing we weren’t distracted by any of this trailing, but it’s subjective and again some users would find it bothersome.

We also tested our Blu-ray film titles, which are limited to ~24fps and noticed no obvious weaknesses related to the pixel responses. The level of fluidity and requirements for pixel response speed are limited by the ‘broken up’ action at such low frame rates. The monitor can be run at 24Hz if preferred, reducing judder for such content. Or you can stick to a multiple of this (144Hz, for example) for decent performance in that respect as well. If you watch higher frame rate content (for example 60fps), some of the weaker pixel transitions do crop up here and there. But never to levels we feel were particularly bothersome – unless you’re running the monitor at 60Hz, which as noted in the FreeSync section and highlighted by TestUFO can become problematic in terms of overshoot.

FreeSync – the technology and activating it

AMD FreeSync is a variable refresh rate technology, an AMD-specific alternative to Nvidia G-SYNC. Both of the articles linked to explore the principles behind variable refresh rate technologies and the benefits that they bring to the experience, so we won’t be repeating everything here. On a basic level, the monitor dynamically adjusts its refresh rate so that it matches the frame rate of the content, where possible. This avoids the stuttering (VSync on) or tearing and juddering (VSync off) that is associated with mismatches between refresh rate and frame rate. In the variable frame rate environment under which the technology is active, FreeSync also promises decreased latency compared to running with VSync enabled.

FreeSync requires a compatible AMD GPU, such as the Club3D Radeon R9 290 royalAce used in our test system. A list of current GPUs which support the technology can be here, with the expectation that future AMD GPUs will support the feature too. The monitor itself must also support ‘VESA Adaptive-Sync’ for FreeSync to be usable. The C27HG70 supports this via DP 1.2+ and HDMI 1.4a+. More specifically, ‘FreeSync 2’ is supported by the monitor, encompassing HDR support and a relatively generous variable refresh rate range. You need to ensure ‘FreeSync’ is set to ‘Standard Engine’ or ‘Ultimate Engine’ in the ‘Game’ section of the OSD. The main difference between these is that ‘Ultimate Engine’ offers a broader variable refresh rate range for FreeSync. Samsung notes that users may experience some flickering with ‘Ultimate Engine’ and should try ‘Standard Engine’ if so. In our testing we didn’t find there to be flickering issues specific to ‘Ultimate Engine’.

After enabling the setting in the OSD, you need to make sure the display driver is setup appropriately as well. AMD’s recent drivers include Radeon Software Crimson, which makes activation of the technology very simple – in fact it should be enabled automatically if a compatible GPU is connected to the monitor and the monitor is in its ‘FreeSync mode’. You can check its status by opening ‘AMD Radeon Settings’ and clicking 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.



If you don’t see this option and you have followed these steps correctly, with a FreeSync compatible GPU, try reinstalling the graphics driver. The Samsung supports a variable refresh rate range of 48 – 144Hz via DP with a lower 100Hz ceiling via HDMI. That means that if the game is running between 48fps and 144fps, the monitor dynamically adjusts its refresh rate to match the frame rate. When the frame rate rises above 144fps, the monitor will stay at 144Hz and the GPU will respect your selection of ‘VSync on’ or ‘VSync off’ in the graphics driver. With ‘VSync on’ the frame rate will not be allowed to rise above 144fps, at which point VSync activates and imposes the usual associated latency penalty. With ‘VSync off’ the frame rate is free to climb as high as the GPU will output (potentially >144fps). With ‘Ultimate Engine’ selected, AMD LFC (Low Framerate Compensation) is supported by this model. This is actually a requirement of FreeSync 2 and means that the refresh rate will stick to multiples of the frame rate when things fall below the 48Hz (48fps) floor of operation for FreeSync. So if the game was running at 32Hz, for example, the monitor would run at 64Hz to keep tearing and stuttering in check. LFC is used regardless of the VSync setting – so the VSync setting only makes a difference above the ceiling of operation (144fps in this case).

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 activate if you enable it within the game itself, if such an option exists. This option may be called ‘sync every frame’ or something similar rather than just ‘VSync’.



There are a couple of final points to note. Firstly, the application must be running in fullscreen mode, not a window (borderless or otherwise). The monitor lists ‘FreeSync’ at the bottom of the ‘Information’ section of the OSD if it’s connected up to a compatible GPU and the option is enabled in the OSD. It also displays a ‘FreeSync 2’ logo inside a monitor. That does not indicate that FreeSync is active at a given moment in time, simply that everything is set up and that it should work when a valid fullscreen 3D application is running. If you observe the refresh rate listed, though, that changes in ‘real time’ if FreeSync is active and the frame rate is fluctuating. It’s a good indication that the technology is doing its thing. The final point to remember is that FreeSync only removes stuttering or juddering related to mismatches between frame rate and refresh rate. It can’t compensate for other interruptions to smooth game play, for example network latency or insufficient system memory.

FreeSync – the experience

We tested a range of game titles to test out the FreeSync capabilities of the C27HG70, including; Hitman, Star Wars Battlefront II, Call of Duty WW2 and Dirt Rally. We found the experience to be rather homogeneous across these titles, so will instead be focusing on just one title; is Battlefield 1 (BF1). This is a good title to use not just because we spend a fair amount of time playing it, but because it offers good flexibility with graphics settings. This allows the full range of FreeSync refresh rates and frame rates to be tested. With our Radeon R9 290, we had to use fairly conservative graphics settings to ensure triple digit frame rates. At the upper end of that, near at ideally reaching 144fps, the full responsiveness benefits of the monitor could be felt. Perceived blur was relatively low and ‘connected feel’ relatively high. There were frequent fluctuations in frame rate and rarely did it stay at the FreeSync ceiling of 144fps (144Hz). Without FreeSync enabled, that would mean that the frame rate and refresh rate would frequently mismatch. Obvious (to us) tearing and juddering ensues in such situations, with VSync off, or obvious stuttering with VSync on. With FreeSync there were no such interruptions to the gaming experience.

As the frame rate dropped, for example closer to 100fps, there was an increase in perceived blur and decrease in ‘connected feel’. However, we felt the experience remained fairly strong in both respects. When it comes to frame rates it’s always a case of ‘the higher the better’, regardless of FreeSync. But these drops in frame rate are easier to stomach with the technology enabled – far less jarring. Having said that, if we increased our graphics settings so the frame rate dropped further (sometimes a lot further), we did start to feel too much of the monitor’s potential drain away. With the ‘connected feel’ being inversely proportional to frame rate and perceived blur levels increasing markedly, even with FreeSync active we found low frame rates an uncomfortable place to be.

As frame rate dropped we also observed more obvious and in places quite ‘in your face’ changes to the pixel response behaviour. Tuning of pixel overdrive to a broad range of refresh rates is often something we find FreeSync models weak at compared to models with G-SYNC. And even with ‘FreeSync 2’ employed here, it seems that trend remained. Below about 80fps there was some obvious overshoot introduced, with bright trailing in places that we found rather eye-catching. Not everybody would be bothered by it and it isn’t as intense as we’ve seen on some models, but it is something that simply wasn’t there at significantly higher frame rates. The section of our video review below shows this and also confirms that the monitor’s LFC (Low Frame Rate Compensation) feature, as we described earlier, works as intended to keep tearing and stuttering at bay. The monitor neatly sticks to multiples of the frame rate for its refresh rate, once the frame rate drops below 45fps.

Impulsive Scanning (strobe backlight)

This monitor features a strobe backlight feature called ‘Impulsive Scanning’ that is activated by setting the monitors ‘Response Time’ to either ‘Faster’ or ‘Fastest’. This causes the backlight to strobe on and off at a frequency matching the refresh rate of the monitor, reducing eye movement and hence reducing perceived blur via the mechanisms explained in this article. If you refer back to the UFO Motion Test for ghosting pursuit photographs featured earlier, you’ll see the visual benefit of this in terms of perceived blur reduction. You can activate this feature at 100Hz, 120Hz or 144Hz. As usual for strobe backlight technologies such as this, you can’t activate it and use FreeSync at the same time. It can be used irrespective of the GPU vendor as well, as it is a Samsung feature that is not specifically associated with AMD or Nvidia (‘ULMB’).

As mentioned previously, once you’ve activated this feature you will see the screen flicker in sync with the refresh rate – much like a CRT monitor. Individual sensitivity to flickering varies, not everyone will find this bothersome, but some will (particularly at 100Hz). We’ve also mentioned previously that the brightness control is locked off, although you can reduce brightness at the expense of contrast using the ‘Contrast’ setting if you must. The monitor appears quite bright with this setting active. We tested a range of game titles using this feature, but as usual we feel it is appropriate to focus on just one to save us repeating ourselves unnecessarily. That title will be Battlefield 1 (BF1), which as you’ll notice by this point of the review has been tested extensively to assess all elements of the CHG70’s performance. We didn’t notice any significant difference between the ‘Faster’ and ‘Fastest’ setting, so this subjective testing can be associated with either mode.

Echoing what we observed using TestUFO, the perceived blur is drastically cut down with this setting active. Soldiers, objects and the game environment all retains superior clarity and detail levels even during rapid movements on the game. For example, cornering quickly in a vehicle or simply running about on foot and using quick snappy movements of the mouse. One significant drawback, which applies more to graphically demanding titles such as this (depending on settings and system), is that the frame rate really needs to match the refresh rate precisely for the mode to work correctly. Because there is very little motion blur to mask stuttering or juddering where these depart, such issues stand out like a sore thumb with the strobe backlight mode active.

Whilst overall perceived blur is hugely reduced, and objects retain superior detail levels in motion, the performance wasn’t particularly ‘clean’. As demonstrated in TestUFO, there was a fair degree of overshoot. This manifested itself as distinctive semi-transparent repetitions of the object, behind the actual thing. They were generally more faint than the main object but appeared as a sort of dulled down grey version of the shades involved in the transition. There were occasional bursts of more colourful (purple) overshoot as well. The fragmented nature of the trailing is due to the strobe backlight operation. In addition to this, some of the pixel transitions were slow enough to provide a sort of ‘smear’ similar to what is observed without the strobe backlight setting active. These weaknesses existed regardless of the refresh rate, although as refresh rate was reduced (as low as 100Hz), the distance between the object and the fragmented trails increased. We found this made the fragmented trailing more noticeable.

This monitor is certainly not unique in showing signs of weakness (particularly the overshoot) with its strobe backlight function active. Although we felt these weaknesses were more pronounced when compared to other monitors that use this sort of technology, including the C24FG70. For some users, the imperfections associated with the strobe backlight setting will still be outweighed by the benefits in terms of perceived blur reduction. Others would find the flickering, lack of FreeSync, lack of HDR, locked brightness, overshoot and fact you need to keep the frame rate matching the refresh rate a bit restrictive.

HDR (High Dynamic Range)

HDR (High Dynamic Range) as it applies to monitors describes the ability to distinctly display very deep dark shades and very bright light shades simultaneously. It is also a requirement to display a huge variety of shades in between, from weakly saturated to heavily saturated shades. The ideal monitor would have hundreds if not more dimming zones on the backlight, something referred to as FALD (Full Array Local Dimming). Even better, it would use a per-pixel light source (OLED technology, for example). This would allow the monitor to correctly display intricate mixtures of bright and dark content, dimming the backlight appropriately for dark content whilst displaying brighter areas of the image with higher backlight luminance. On the colour side the ultimate goal is for HDR monitors to offer a huge colour gamut (Rec. 2020). The more realistic near-term aim, as proposed by the UHD Alliance, is to cover 90% DCI-P3 (a Digital Cinema Initiatives standard colour space). It is a requirement 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.

We’ve already explored how some HDR solutions merely respond to HDR content sort of like a Dynamic Contrast mode on a regular monitor. Something we’d dub ‘fake HDR’. They control the backlight as a single unit, don’t have a noteworthy maximum luminance and fall short of the DCI-P3 colour space by some margin. We’ve also noted that Windows 10 users with the ‘Creator’s update’ need to be wary of a Windows feature called ‘HDR and advanced colour’. As a quick reminder, this is a feature found in ‘Display settings’ (right click the desktop) and it may be enabled by default. It might make everything look highly flooded on the desktop and you’ll think the monitor is malfunctioning. Simply turn this feature ‘Off’ if it’s enabled and you notice the desktop looking odd – the monitor will whack itself into HDR mode for fullscreen applications that support an HDR signal regardless of what this feature is set to. This toggle is shown in the image below.

We’ve also previously highlighted how software support for HDR is quite variable on the PC. Many titles don’t support it at all and some (such as Mass Effect Andromeda) support it poorly. Back to the hardware side, the Samsung C27HG70 responds to HDR content with both compatible AMD and Nvidia GPUs. In fact we tested the feature with our Nvidia GTX 1070 via DP 1.4 as our AMD Radeon R9 290 doesn’t support HDR due to older HDMI and DP revisions being used. This model doesn’t offer an FALD backlight solution or similar, but it does split the backlight into multiple dimming zones. You have to make sure ‘Local Dimming’ is set to ‘On’ or ‘Auto’ in the ‘System’ section of the OSD. Samsung doesn’t officially specify how many, but our testing and testing done by others suggests that there are 8 dimming zones for the backlight. Some of these zones can be very bright and others very dark (or in between). We’ve already covered, in the contrast section, that the maximum luminance with ‘Local Dimming’ active is just over 600 cd/m² which exceeds the usual maximum luminance of the display. If the feature is enabled and you’re viewing SDR (‘normal’) content, the backlight zones never dim effectively. In HDR the zones become more reactive and dim to lower levels, fortunately.

So how does this work out in practice? The image below, from Battlefield 1 with HDR10 (current PC standard for HDR), gives an example of the sort of scenario that was enhanced by the HDR capability of the monitor. This is just to set the scene and fire up your imagination; it in no way demonstrates what this scene looks like whilst viewing it first person of the CHG70. Also note that we tested a few other titles which we feel implemented HDR quite well, with Hitman being particularly impressive. To keep things as succinct as possible, we’ll just be focusing on BF1 as our specific example for this section. Note that we used our Nvidia GTX 1070 to test HDR on this monitor, connected via DP.

Even with a relatively low number of dimming zones, we found the shifts in brightness of the different zones to be quite natural and not jarring like a normal Dynamic Contrast setting. The dark areas of the image also remained significantly dimmer than the monitor running at ‘100’ brightness without HDR active. As such subtle details on the rocks appeared more clearly than with HDR disabled, where everything is just flooded by an excessively bright backlight. Ideally the stars would appear as quite bright pin-pricks in the sky, whilst the sky itself would appear fairly deep. That isn’t how things played out, as it would require many more dimming zones to simulate effectively – ideally per-pixel lighting. The monitor therefore balances things out based on the average luminance in those regions. The moon appeared very bright and in some ways akin to staring at the real moon, almost retina-piercing if you’re sitting staring at it in a darkened room. This contrasted very nicely with those dark rocks to the immediate right of the character, which covered a different dimming zone. If you preferred bright elements like the moon not being so piercing, you can limit the effect by simply lowering the brightness. We used ‘100’ just for the full effect. We wouldn’t generally recommend keeping the brightness that high if you’re gaming in a dark room, unless you really want that kind of dazzling experience. We carried out most of our testing with at least some ambient light from the room itself.

What was in some ways more impressive than these situational improvements was the fact that we didn’t actively notice that the backlight was split into zones. Nor that it was continuously adjusting the brightness of those zones. We find traditional Dynamic Contrast modes, where the whole screen reacts, quite distracting whilst adding little if any positive benefit to the experience. This solution seemed to be integrated in a way that was subtle enough to add something to the experience without the jarring side-effects. This could be considered subjective and we’re sure not everybody would agree with this assessment, but we do find the addition of even a mere 8 dimming zones to be welcome. And if you don’t agree, of course, you can simply request that the monitor doesn’t use them by disabling the ‘Local Dimming’ feature in the OSD.

Regardless of whether ‘Local Dimming’ is active, there are other benefits beyond this. The distinctions between closely matching bright and dim shades was aided by 10-bits per channel precision. HDR works with this at the software level to make use of this level of precision, whilst the monitor supports such a bit depth as well. This bit depth allows shades to be more precisely mapped across its fairly generous colour gamut. As a reminder, the native colour gamut (under our ‘Test Settings’) is shown below. If anything, it’s slightly under-represented in this diagram due to limitations with the Spyder5ELITE sensor. The monitor offers good DCI-P3 coverage, with Samsung specifying 95% – exceeding the 90% DCI-P3 coverage currently targeted by the UHD Alliance.

Colour gamut 'Test Settings'

Remember that the monitor supports this large gamut with 10-bits per subpixel precision. As we’ve explored in the ‘Colour Reproduction’ section of the review, the gamut leads to some oversaturation with normal SDR content. With HDR content, such as BF1 with HDR10 active, shade saturation is mapped more appropriately. The greens of vegetation appear more natural, with more muted shades appearing appropriately dusty and ‘pastel’ rather than overly bright or saturated. There remains an excellent variety and there are plenty of lush shades, where appropriate, with some shades far deeper than would be displayed within the confines of the sRGB colour space. There is also a more believable representation of more Khaki shades. The sands of the desert loose the slightly overdone reddish hue as well – it retained in places, where the developers intend, but isn’t as widespread or as intense. Meanwhile, excellent vibrancy and strong saturation is retained where it is wanted. The orange, reds and yellows of flames and brilliant reds of poppy flowers, for example.

Overall, we certainly enjoyed experiencing HDR content on the CHG70 and feel that the monitor supported this content quite well. It certainly wasn’t a ‘full fat’ experience, as the limited number of dimming zones and good but not extreme colour gamut restricted the contrast and colour reproduction, respectively. But it was a lot more enjoyable than the ‘fake HDR’ employed by some monitors and it gave a nice taste of what we can expect from HDR content in the future. It’s certainly a trend we feel manufacturers will push more into the future, with more widespread support on both the software and hardware side. This will only be a good thing for gamers.

The 27″ 2560 x 1440 curved experience

We’ve used various curved monitors of various sizes and steepness of curvature and commented on what the curve brings to the experience. The C27HG70 brandishes a 27” screen with 1800R curve and 2560 x 1440 (WQHD) resolution. Users are generally quite familiar with the advantages of this resolution over the Full HD (1920 x 1080) resolution. It works nicely with a screen of this size, providing a good but not extreme pixel density and providing a level of clarity in games, movies, images and text that most people would find quite pleasing. Without needing to reach for the scaling slider in Windows as the first thing they do. If users think about a curve, especially one of 1800R (which is relatively steep – especially compared to earlier models that were 3000R – 4000R) they are often put off by the thought of it. They think things are going to look heavily distorted, unnatural and simply wrong. Sometimes these preconceived notions are reinforced when they look at images of the screen, where the curve may sometimes appear as quite a prominent feature.

We were guilty of having similar thoughts ourselves, before we had ‘on the desk’ experience with curved monitors. We find the 1800R curve on the 27” CFG70 to be quite a subtle addition and one that is very easy to adapt to and get used to. Samsung would claim that viewing comfort is a big advantage of the curve and possibly cite some studies as proof of this. After all, the edges of the screen are brought closer to the eyes so that the experience is more uniform. And our eyes are curved rather than flat. We certainly found this monitor comfortable to use, but how much of that is down to the curve is difficult to say. The images below tend to exaggerate the curve, but are included for illustrative purposes. You can also see the WQHD in action, giving you a nice amount of useful desktop ‘real-estate’. In terms of overall clarity, we prefer the tighter pixel density of this model (108.79 PPI – Pixels Per Inch) over the 31.5” variant (93.24 PPI). That’s a personal thing, though, and we can also see the attraction of the physically more imposing 31.5” screen.

When it came to gaming, the curve brought with it a slight extra feeling of depth. It’s something that’s quite difficult to describe and again quite subtle, but it just draws you into the game environment that little bit more. This effect is certainly more subtle than it is on wider screens, particularly curved UltraWides of a similar or steeper curvature. But it’s still there. Some would also argue that the more uniform viewing distance of different points of the screen and reduced eye movement required when scanning peripheral sections of the screen is advantageous. The images below are again just for illustrative purposes and tend to exaggerate the curve somewhat.

Interpolation and upscaling

Not all users will want to or be able to use the native 2560 x 1440 (WQHD) resolution all the time. They may be running a system, such as a games console, that doesn’t support the resolution. Or perhaps they are finding it too demanding for games or other intensive applications. If you set the monitor to a lower resolution, such as 1920 x 1080 (Full HD or ‘1080p’), the monitor uses an interpolation process to output an image. Note that this requires that the monitor is connected via HDMI and running at 60Hz max, as no scaling capability on the monitor itself is provided via DP or for higher refresh rates. For optimal quality you need to ensure it is the monitor rather than GPU handling the HDMI interpolation. 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 provides a somewhat softer look to the image compared to a native Full HD display of similar size. Some finer texture detail is lost, edges appear softer and particularly if you look into the distance things just aren’t quite as sharply defined as they should be. This is less severe that we’ve seen on some models, though, as things don’t look extremely blurry or as if some sort of soft-focus filter has been applied. Some users may prefer to increase the sharpness level in the OSD, perhaps to ‘64’ for example. This gives a somewhat artificial overly-sharp (but still lacking definition) look in our view but it would come down to personal preferences. We feel that the interpolation mode is decent if you need to use it (on a non-UHD games console perhaps), especially if you’re sitting back a bit from the screen so that the imperfections are more difficult to notice.

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

Video review

The video below summarises some of the key points raised in this written review and shows the monitor in action. The video review is designed to complement the written piece and is not nearly as comprehensive.

Conclusion

The Samsung C27HG70 was always an interesting monitor on paper, featuring a 27” 2560 x 1440 (WQHD) VA panel. That alone is a rarity, but it is also coupled this with a 144Hz refresh rate. The 1800R curve to the screen is something we’ve experienced a fair bit on monitors of various sizes and our experience here reinforced our feeling that it’s a nice but relatively subtle addition. The monitor was comfortable and natural to use (how much of that was down to the curve is debatable), with the curve drawing you into the image a little bit more. The WQHD resolution on a 27” screen is certainly nothing new, but it yielded a pixel density that we preferred to its 31.5” brother. That’s a personal preference, however. The screen surface was a bit grainier than we would have liked, though, affecting the smoothness of lighter shades. We’ve certainly seen a lot worse when it comes to grainy matte screen surfaces, but we’ve seen better as well.

The contrast performance of the monitor was quite strong, as you’d expect from a VA panel. It fell slightly short of the specifications in our measurements, but it certainly felt like a VA model. It had a depth to dark shades and contrast between dark and light shades that other LCD panel types just can’t match. The lack of ‘IPS glow’ was a nice addition, although it was replaced by ‘VA glow’ which was a bit higher in this case than on some VA models. There was a bit of ‘black crush’, although nothing substantial and about as little as we’ve seen from a VA model of this size really. The colour performance was pleasing overall, especially in terms of vibrancy. The generous colour gamut (well beyond sRGB) really helped in that respect, particularly coupled with the fairly strong contrast and the light matte screen surface. This allowed more direct emission of light than ‘stronger’ matte screen surfaces, without a layer of smeary grain between your eyes and the image. Colour consistency was good for the panel type, but there were still shifts in perceived gamma and saturation depending on which part of the screen you’re observing. That issue generally makes this sort of model less suitable than IPS-type panels for colour critical work.

The C27HG70’s HDR capabilities helped put the colour gamut, which falls just short of DCI-P3, to good use. When consuming most content, which is designed with the sRGB colour space in mind, the native gamut of the monitor gives a bit of oversaturation. It isn’t extreme as it is when viewing such content on a monitor with a traditional wide gamut, such as Adobe RGB. But it’s still there. HDR content is potentially mapped more accurately to the gamut, complete with 10-bit precision. This content can be and often is specifically engineered to fit that sort of >sRGB gamut. So things appear more natural, but you get some really nice vibrant elements where the creators intend them – or they can just go all out and make everything vibrant, if they so desire. We found the local dimming aspect of HDR to be surprisingly decent. Whilst it would have been much better to have hundreds if not more local dimming zones or ideally per-pixel lighting, we still feel splitting the backlight up into a mere 8 zones was beneficial compared to having a single backlight unit. It couldn’t account for intricate mixtures of light and dark, of course, but did enhance the overall in many scenarios. It’s clear that the HDR experience can be made superior by that sort of thing, plus an even more generous colour gamut (Rec. 2020, perhaps), but this was a decent attempt and better than the ‘fake HDR’ found on many models out there.

Responsiveness was quite good, overall. There was very little input lag to speak of and the monitor put its 144Hz refresh rate to good use. The ‘connected feel’ was greatly enhanced compared to lower refresh rates and lower frame rates, with a similarly pleasing reduction in perceived blur. There were some notable weaknesses in pixel responsiveness, though, which always occur to some degree with VA panels. There was some ‘smeary’ trailing, some ‘break-up’ trailing and some overshoot in places. These issues were most pronounced where dark shades were involved in the transition. This was far from being the worst VA model we’ve seen in any of those respects, even amongst high refresh rate models. But it wasn’t the best, either. We feel the overdrive could have been a bit better tuned and a bit more flexible, taking the edge of this a little bit in places.

FreeSync was a nice addition and did its usual thing, taking tearing and stuttering from frame rate and refresh rate mismatches out of the equation. It also offered a good range of operation and full support for LFC, part of the requirements for ‘FreeSync 2’ (alongside HDR support) as this model features. However; we noticed some quite obnoxious overshoot as the frame rate dropped into the double digits, particularly below about 80fps. If you leave the monitor at a static refresh rate that isn’t an issue, but with FreeSync the refresh rate is lowered at the same time. The monitor had similar issues at a static refresh rate of 60Hz, which could potentially cause issues for users who are forced to use that (games console, for example). We often see some imperfections in that respect when it comes to FreeSync – things are usually better tuned for lower refresh rates on G-SYNC displays. We were hoping FreeSync 2 might improve that aspect, but that wasn’t the case. A more flexible pixel overdrive solution would have been helpful, with the ‘Faster’ and ‘Fastest’ settings instead reserved for the ‘Impulsive Scanning’ strobe backlight setting of the monitor. This worked as intended to decrease perceived blur, but it wasn’t without its imperfections. The flickering (unavoidable – it’s how it works), greyed out brightness setting and pixel responsiveness imperfections that were retained won’t appeal to everyone.

Anybody who is used to reading our reviews will know that all monitors have distinct strengths and weaknesses. Some of the weaknesses we like to highlight aren’t even going to be noticed by some users or they simply won’t be things they mind. After all, no monitor is perfect and this is no exception. On balance, though, we feel that this monitor offered an enjoyable gaming and general computing experience. Its combination of panel type, resolution, size, refresh rate plus support for HDR (any compatible GPU) and FreeSync (any compatible AMD GPU) are sure to please many users. It certainly ticks a lot more boxes than it misses out on ticking. If you’re keen on a high refresh rate monitor, like a rich and colourful gaming experience and fancy taking advantage of HDR then this monitor is strongly worth considering. If you’re looking for super-consistent colours or a ‘clean’ high refresh rate motion performance, then you might want to look elsewhere.

The bottom line; a monitor with an appealing feature-set for gaming in particular, delivering a rich and responsive gaming experience in SDR and HDR.

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