Samsung S27E650C

Responsiveness

Input lag

Using a sensitive camera and small tool called SMTT 2.0, we compared the latency of the S27E650C with a range of monitors of known latency. By taking over 30 repeat readings using this method, we measured 6.10ms (around 1/3 of a frame) of input lag. This value is influenced both by the element of input lag that you feel (signal delay) that you see (pixel responsiveness). This value indicates a very low signal delay that shouldn’t inhibit the gaming experience.

Perceived blur (pursuit photography)

In this article we explore the key factors that contribute to the responsiveness of a monitor. Amongst these is the very important concept of perceived blur and that the movement of our own eyes contributes heavily towards this. The idea of ‘pursuit photography’ is also explored, a method which uses a moving camera to capture motion on a monitor in a way that quite accurately reflects what the eye would see. This includes not only perceived blur due to ‘eye’ (camera) movement but also shows any weaknesses caused by slower than optimal pixel responses or inverse ghosting (overshoot) due to overly aggressive pixel overdrive (grey to grey acceleration).

The images below are pursuit photographs taken on the UFO Motion Test for ghosting, with the test running at the default speed of 960 pixels per second. Such a speed is practical for taking such photos and highlights any issues on the test nicely. The first column shows results with the dark cyan background whilst the second column shows the medium cyan background (top and middle row of the test, respectively). All response time settings on the monitor were tested as well as a capture with the monitor running at 72Hz, which this monitor will also do comfortably as we’ll come onto later. The bottom image shows a ‘Fast 60Hz reference’, which is a Samsung S27A750D set to full brightness (forces DC dimming, without flicker) and 60Hz using its ‘Faster’ response time setting. This reference shows how things should look in this test at 60Hz where motion blur due to eye (camera) movement is the only real limiting factor.

Perceived blur with various settings

Using the ‘Normal’ setting, you can see a fair degree of blur behind the object, particularly with the dark cyan background. This is trailing from slower than optimal pixel responses. Using the ‘Faster’ setting appears to improve things a little for the dark background, whilst for the medium background things remain much the same. This is certainly not the most extensive trailing you’ll see on a VA panel and in fact for the particular transitions shown here with the dark background, it’s actually fairly tame. Using the ‘Fastest’ setting appears to reduce the trailing a bit more for the dark background, but there is actually a bit of overshoot (inverse ghosting) introduced here as well. It isn’t clear on the image, but behind the yellow UFO cockpit in particular there is a dark shadow-like trail that’s darker than the background colour. For the medium background you can see some overshoot here as well.

Considering a broader range of pixel transitions than those shown here is quite important on VA panels in particular where there can be significant variation depending on the shades involved in the transition. This test does seem to suggest that the ‘Faster’ response time offers the best balance of acceleration but that there are some weaknesses, particularly for the darker background. In practice there is some overshoot here and there as we’ll come onto later, that isn’t apparent on the particular transitions shown here. There is extremely noticeable overshoot in places using the ‘Fastest’ mode, though, so we avoided that setting.

Having established the default ‘Faster’ setting to be optimal, we took captures at 72Hz as shown here. You can see that the object itself appears more compact, but that the trailing behind the object remains much as it does at 60Hz. That is because the motion blur related to eye (camera) movement is reduced in accordance with the increased refresh rate, but the pixel responsiveness remains unchanged. Again the differentiation here is explained more clearly in our responsiveness article. How does this work out in practice? Well, whilst running the monitor at 72Hz with 72fps content instead of 60Hz with 60fps content, you can notice this slight decrease in overall motion blur. But there are some slower pixel responses that give trailing on top of this regardless of the increased refresh rate – the trailing there is much the same. You also get a slightly more ‘connected feel’ due to a decrease in the delay between frames on the monitor – with up to 1.2 times as much information displayed by the monitor every second. This is of course all quite subtle compared to running at a much higher refresh rate such as 144Hz, but some users will see it as a nice bonus nonetheless.

Running a custom resolution (overclocking)

The monitor will comfortably run at up to 72Hz at 1920 x 1080. With this we mean the monitor will run at this refresh rate without implications for image quality (changes to gamma, contrast, colour temperature etc.) and without skipping frames. Regardless of the input used, the monitor refuses to run higher than this at 1920 x 1080 due to a built-in safeguard. A ‘Not Optimal Mode’ message will bounce around the screen if you attempt to run beyond this regardless of any timing adjustments you may have made. To run the monitor at 1920 x 1080 @ 72Hz you must create a ‘custom resolution’. There is no need to modify timings, so the process is quite simple. The video below runs through how this can be done using the Nvidia Control Panel, or for AMD users, using a tool called CRU (Custom Resolution Utility).

Bumping up this monitor to 72Hz is what we consider to be a ‘mild’ overclock, which the screen handles very comfortably. There is minimal risk involved and in all likelihood the monitor will last for its useful life in much the same way as if it was run at its native 60Hz refresh rate. Despite this, you must be aware that overclocking is something which you do at your own risk. The risk may well be very low, but we accept no liability should anything happen to the monitor which may or may not be due to running it at an increased refresh rate. For purposes of the review, including the testing below, we kept the monitor running at 60Hz as normal.

Responsiveness in games and movies

On Battlefield 4 it was clear that eye movement was the key (although not sole) contributor to the overall perceived blur on this monitor. Many of the transitions actually occurred rather quickly – quickly enough, in fact, to provide an optimal experience within the confines of the 60Hz refresh rate. This was certainly one of the faster Vertical Alignment models we’ve used and it is quite a distant experience from the smeary mess that slower VA models can produce. Having said that (and as identified by earlier testing) there was some additional trailing in places to add to the perceived blur. In most instances there was sometimes a fairly faint whiff of trailing from slower than optimal pixel responses, adding just a subtle touch of extra blur in places. This was most noticeable when cornering in a vehicle, adding a little extra to the dizzying sensation some users might experience at times. Other users would be hard pushed to notice this even in a side-by-side comparison with a faster monitor, however.

Where very dark shades were introduced into the mix, this trailing increased – but not to the extent of ‘smearing’ as you see on many VA models. It was clear that very effective grey to grey acceleration was being employed. That wasn’t entirely without its consequences, though. There was a moderate degree of overshoot in places, most noticeable where there were very light objects with a much darker background shade. Where you moved past tan-coloured vehicles against a deep blue sky, for example, you could see a sort of shadowy blue that was darker than the sky colour. This is shown in the video below. And likewise when looking through thermal objects with white hot objects against a ‘cool’ dark grey background, there was a trail that was darker than even the background colour. Again, not all users would notice this when playing and it was far from the most obtrusive overshoot we’ve seen. Still worth noting, though.

Dirt Rally provided a similar experience. For the most part the 60Hz refresh rate and movement of the eyes were really the thing holding back the visual responsiveness. This was a far cry from the smeary ‘smoke-like’ trails that grace many VA models and even the slightly extended trailing that some of the newer ‘AMVA+’ models still suffer from. Even when driving at night the experience wasn’t spoilt by the extent of trailing you’d usually see on ‘high-contrast transitions’ between light and dark shades. Again, there was certainly some trailing beyond what you’d ideally see on a 60Hz LCD but nothing too obnoxious. There was also some overshoot visible in places, perhaps most noticeable at night as it stands out a bit better when it is lighter than either the object or background colour. When driving past trees in the dark with the night sky above, for example, there was a trail of a brighter shade of blue than the sky itself. When moving past telegraph posts that appeared a slightly lighter shade than these trees, with the same night sky in the background, you could see a sort of semi-transparent ‘snail slime’ trail.

Overall this is one of the more competent VA monitors we’ve used for gaming, as it doesn’t impede the experience with smeary trails or a huge degree of overshoot. There are still some weaknesses in places and a bit of overshoot as well, but nothing like we’ve seen on some models. On the subject of weaknesses in responsiveness, none cropped up when watching our Blu-ray film titles. We didn’t see any obvious overshoot (perhaps small traces here and there) nor any obvious trailing from slower than optimal pixel responses. These titles run at 24fps, so the requirements for ‘optimal performance’ and the overall influence of pixel responses is quite different.

The curve

Samsung are keen to stress the idea that having a slight concave curve to the screen can enhance viewing comfort by bringing the edges of the screen closer to the viewers eyes, reducing eye movement and creating a more uniform and ‘natural’ viewing experience. We’ve previously explored what the slight (3000R) curve brings to the table on models like the Samsung S34E790C. The curve on this model is even gentler at 4000R – and of course as the screen itself isn’t as wide it is far more subtle. It is so subtle in fact, that it was barely noticeable. Even if you were viewing straight lines (for example, in Excel), there was no distortion or anything like that. You could tell the monitor was curved by carefully scanning your eyes across the screen and comparing what you can see in the centre vs. the far edges – but it really doesn’t jump out at you when viewing normally. The following images show an Excel spreadsheet and website, respectively. These are mainly for illustrative purposes and don’t really capture what it is like to see the monitor in person. Apologies for the curved bands, which are not visible on the monitor itself and are purely moiré from the camera.

The take home message is essentially that we find the ~32” screen size to be something of a sweet spot for the UHD resolution. It provides a comfortable viewing experience without scaling for us from our preferred viewing distance of ~70cm – although mileage may vary according to preferences, eyesight and preferred viewing distance. This provides a large working area both in terms of physical space but also, importantly, useful work area. Text and image clarity is excellent and you can fit a lot on the screen at once, as demonstrated by the images below.

It certainly didn’t change the viewing experience for us when gaming or watching movies. The effect was quite subtle as it is on the 34” UltraWide models with their 3500R and wider screens. Enough to add just a little bit of extra depth and perhaps make the viewing a bit more comfortable. On the S27E650C, though, it was really quite easy to forget you were even gaming or watching a movie on a curved screen. That can be considered either a good or bad thing depending on your perspective. It makes the general experience of using the monitor quite familiar to those that have used 27” monitors before and doesn’t cause things to look ‘weird’ or anything like that. But it doesn’t really add much to the experience, by the same token. The images below are purely for illustrative purposes and don’t capture what the monitor was actually like in person. Sorry again about the camera moiré.

Conclusion

The Samsung S27E650C arouses much curiosity due to the fact that it has a gentle curve to it. It also uses the Vertical Alignment panel type, which is less ubiquitous than IPS in particular these days but offers an attractive alternative for users who value contrast and low likelihood of uniformity issues during dark scenes. The curve on this monitor is subtle and, when coupled with the size of the screen (which doesn’t really take advantage of that fact to the degree that an ‘UltraWide’ model might) it is difficult to notice. It’s certainly not something we’d use as a deciding factor if you’re considering purchasing this monitor or a similar model.

Curve aside, this monitor did get a lot of things right. Aside from the high default brightness, which is fully expected from a modern monitor, the out of the box image setup was excellent. Gamma tracking was pleasing and white point was right where most users would want it if they’re targeting the common 6500K ‘daylight’ white point. There was some loss of saturation further down the screen in particular, and to a lesser extent the flanks, but this was as subtle as we’ve seen on a 27” VA panel. The overall image was rich with good variety. The colour gamut was not as extensive as you’d see on some models, particularly higher resolution models with extension beyond sRGB in all sectors. However; coverage of the sRGB space was still good and there was some extensions in the green region for a little extra vibrancy.

Contrast is of course the main strength of VA panels and in that respect the monitor didn’t disappoint. Static contrast was right where you’d expect it to be based on the specifications – around 3000:1. This provided a fairly deep and inky look to text and other dark elements, with bright elements standing out with quite some brilliance against darker surroundings. Other pleasing aspects related to this included the lowest level of ‘black crush’ we’ve seen on a VA model and a screen surface that wasn’t obtrusively grainy. We did notice that the pixels are a bit squat on this monitor, though, with slightly larger gaps above and beneath pixels than is ideal. This caused visible interlacing on various shades. Although this was very faint and not something everybody would notice, it could certainly irk some users.

The Achilles heel of the VA panel is responsiveness. In this respect the monitor actually fared rather well. There were some weaknesses here and there, including a bit of overshoot in places and some transitions that were slower than optimal for the 60Hz refresh rate. Giving a bit of extra trailing. But these issues were both far more subtle than we’ve seen on many other models and in many respects this was one of the most useable VA models we’ve tested for gaming. Input lag was also nice and low, which shouldn’t pose a problem even for users who are sensitive to it. The monitor also overclocked quite happily to 72Hz – which may not sound like much to some people, but did give a nice little boost in responsiveness. It didn’t change the pixel response behaviour, but it did add to the ‘connected feel’ a bit when gaming and reduced perceived blur a touch as well.

Overall the S27E650C ticks a lot of boxes. In fact, if it wasn’t for the faint interlacing patterns that our keen eyes noticed, we’d quite happily recommend this model quite openly. We’re also aware that Samsung have a number of other curved 27” models including the S27E510C and S27D590C. Dell also have the SE2716H. This review should give a rough idea of what to expect from those models, as they use the same (or in the case of the S27E510C, a similar) panel and it is clearly quite capable in some areas. Some of those models are more widely available and cheaper than the S27E650C, too. It is worth mentioning the overall design of this monitor and the range of ports, though, which is a potential advantage over many of the other 27” curved models.

The bottom line; this monitor offers a strong performance in many respects, but don’t buy it for the curve as it’s such a subtle addition that it generally goes unnoticed.

 

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