Samsung S24E390HL

Responsiveness

Input lag

Using a sensitive camera and small tool called SMTT 2.0, we compared the latency of the S24E390HL with a range of monitors with known input lag. Using this method and taking over 30 repeat readings, we measured 5.38ms (around 1/3 of a frame) of input lag. This value is influenced both by what you feel when using the monitor (the signal delay) and also what you see (pixel responsiveness). This value indicates a very low signal delay which shouldn’t concern most gamers who are happy with a 60Hz display.

Perceived blur (pursuit photography)

In this article we explore the key factors that contribute to the responsiveness of a monitor. We explore the very important notion that what you see on a monitor in motion depends not just on what the pixels themselves are doing, but also what your own eyes are doing. They move to track motion on the screen, which itself induces a level of blur that is strongly influenced by refresh rate. We also introduce the concept of ‘pursuit photography’, which uses a moving camera to capture the motion performance of a monitor in a way that reflects what the eye sees. This method captures what the monitor’s pixels are doing (including any conventional trailing or ‘inverse ghosting’ that may occur) but also reflects perceived blur due to physical movement of the camera (‘eye’).

The following images are pursuit photographs taken using the UFO Motion Test for ghosting. This is running at 960 pixels per second, a practical speed to record such images and sufficient to highlight what the pixels are doing. The middle row of the test (‘medium cyan’ background) is used throughout with the monitor set to various response time settings; ‘Normal’, ‘Faster’ and ‘Fastest’. There is also a capture taken with the monitor running at 75Hz, something it can do comfortably at the native resolution as we come onto a little later. And finally there is a 60Hz reference monitor, a Samsung S27A750D set to full brightness (eliminates PWM) and 60Hz, using its ‘Faster’ response time setting.

Perceived blur with various settings

Using the ‘Normal’ setting, you can see quite a significant degree of blur on top of what you would ideally see at the 60Hz refresh rate (i.e. the 60Hz reference). This is due to response times during these transitions being sluggish. Using the ‘Faster’ setting activates the pixel overdrive (grey to grey) acceleration of the monitor and very effectively speeds up these transitions. There is still a little bit of blur on top of the 60Hz reference, but this is massively reduced compared to the ‘Normal’ setting. Using the ‘Fastest’ setting ramps up the grey to grey acceleration so that it becomes overly aggressive. Although that little bit of extra conventional trailing has now been cut back, a far more obtrusive spate of inverse ghosting (overshoot) has been introduced. This manifests itself as eye-catching blue trails behind the object.

We also tested the monitor at 75Hz using the optimal ‘Faster’ setting, which cut down on the perceived blur in this test compared to running the monitor at its default 60Hz. If you focus on the head of the alien you can see that it is a bit better defined than at 60Hz. The ‘legs’ at the bottom of the UFO are clearer than even the 60Hz reference now. In addition to the perceived blur being reduced, where the frame rate exceeds 60fps and ideally matches the 75Hz refresh rate (i.e. 75fps), there is an increased ‘connected feeling’ with the display. There is a decreased delay between frames and more content (up to 1.25 times) being displayed every second. Obviously this doesn’t give the same experience as you’d get on a 120Hz or 144Hz monitor, but it still gives a bit of an edge over 60Hz which some users would appreciate.

Running a custom resolution (overclocking)

The monitor will comfortably run at up to 75Hz at 1920 x 1080 when connected by HDMI. By this we mean there is no change in image quality (gamma, colour temperature, contrast etc.) and no frame skipping – so it is ‘true 75Hz’. We could actually push the monitor to 76Hz with default timings, but any higher and there was obvious degradation in image quality (i.e. complete loss of sharpness and then flickering artifacts). In order to run the monitor at 1920 x 1080 @ 75Hz you must create a ‘custom resolution’. There is no need to fiddle with timings or anything like that, so it’s a fairly straightforward process. 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).

This is what would be considered a ‘mild’ overclock for a monitor and one 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. Even so, as with any form of overclocking you’re doing this 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 the sake of this review, including the section that follows, the monitor was run at 60Hz as normal.

Responsiveness in games and movies

On BF4 things were largely as you’d see on even the fastest 60Hz monitors. There was a moderate blur when running about on foot or zipping about in a vehicle. This was primarily caused by eye movement, and for the most part pixel responsiveness did not present any weakness on top of this. There were a few transitions that appeared to be slower than optimal, but not worryingly so. Where bright shades moved against darker shades there was a bit of extra trailing on top of what you’d expect from a ‘perfect’ 60Hz sample and hold reference. The best example of this was when viewing white hot objects using the thermal optics of a vehicle. The cooler backgrounds generally appeared a medium-dark grey which contrasted well with the bright white objects – the trail behind those white objects was somewhat more pronounced than it could be. We didn’t feel this was really significant enough to impede a user’s enjoyment and indeed it’s not the sort of thing most users are even likely to notice. Overshoot (inverse ghosting) on the other hand can be quite obtrusive and noticeable – but fortunately there was no significant overshoot from this monitor. There were very faint traces here and there that you’d really have to look out for to notice.

Our observations were similar on Dirt 3. The blur was, again, predominantly caused by eye movement rather than slow pixel response times. And indeed for the most part pixel responses were just as snappy as they needed to be for optimal 60Hz performance without introducing either trailing or noticeable overshoot. When driving at night some of those slightly slower pixel transitions came into play, for example lights and torches set against a murky background. Even here the extra little bit of trailing was not at all problematic and didn’t really impede the experience. All IPS-type panels have some pixel transitions like this that are a little bit slower than optimal, unless they ‘hide’ them by strong acceleration that gives a bit of overshoot instead. The predecessor to this monitor (S24D390HL) also exhibits a bit of trailing above what is optimal here and there – and it also has a little more overshoot than this model. Really we feel the balance Samsung has struck here is as good as you’ll see from an IPS-type 60Hz monitor. And if you find things problematic it’s more than likely that you’d be dissatisfied with any 60Hz LCD.

To round off this section we fired up our Blu-ray movie test titles to see if there were any problems with responsiveness there. There was nothing that stood out, even under close scrutiny, as the pixel responses were more than fast enough to handle the pace of action here. Furthermore they did so without any noticeable overshoot being introduced. The fluidity of action on these films is limited by the 24fps at which the titles run, but that isn’t something the monitor itself can address.

Conclusion

The Samsung S24E390HL is the successor to the S24D390HL, a monitor for which we have been full of praise and happily recommending to users. Without shifting away to using a different panel, there was really little that could be done to improve on the core performance of the SD390. Indeed the SE390 offered a similar experience overall, which is largely a good thing. The ‘out of the box’ image setup was very good, requiring some tweaks to colour channels but with excellent gamma tracking using the default mode. Colours had that richness and variety we’d hope for from an AD-PLS panel with generous sRGB colour space coverage. The screen surface also aided the vibrancy somewhat, but moreover gave the image less of a grainy look than monitors with comparable AH-IPS panels.

Static contrast was quite strong overall, slightly exceeding the specified 1000:1 even following the adjustments made to our ‘Test Settings’. There was the usual ‘PLS glow’, which ate away at some of the peripheral details in dark scenes. A new feature added to this model is the ‘Eye Saver Mode’. This proved to be an effective ‘Low Blue Light’ setting, although we didn’t find the huge hit in contrast necessary for our own visual comfort when using the screen and therefore preferred to use the ‘Warm2’ colour tone to reduce blue light output. Responsiveness was also pleasing, with very little input lag and well-tuned grey to grey acceleration. There were some pixel responses that were just a little slower than would be optimal for a 60Hz LCD, but overall things were as good as you could hope for from such a model. The responsiveness was similar to the SD390, with a slight cut in already very low levels of overshoot using the optimal response time setting.

The most notable changes to the monitor were aesthetic and structural. The stand is more similar to that used on the S24D590PL than the S24D390HL; with a T-shaped base and broad stand neck that offers superior stability or ‘wobble resistance’. The JOG button (joystick) used to control the OSD was also carried over from the SD590 series. So no longer do users have to choose between the more solid construction and convenient OSD control of the SD590 series or the superior image setup of the SD390 series. Overall we feel this is a monitor worthy of praise. Although not hugely different to its predecessor, we feel that Samsung did well to take the “if it ain’t broke” approach to the image setup whilst improving exterior qualities and features.

 

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