SAMSUNG S90F (WOLED) vs TCL C6KS / C69KS / Q6CS

Does the S90F handle not only blacks but also bright parts of the image? Definitely. The stories about OLEDs as "dark screens" can slowly be regarded as myth. The Samsung S90F, like the LG C5 based on a very similar panel, achieves brightness exceeding 1000 nits. This is a value more than enough to enjoy impressive and dynamic HDR images – both in movies and series. Most of the scenes we tested look stunning, with well-defined highlights and high contrast. Of course, OLED technology still has its limitations – in very bright, full-screen sequences, such as the test card from the movie The Meg (photo 5), the television may noticeably dim the image. However, it should be emphasized that such scenes are rare. It can be said that the HDR effect is good enough that even mid-range OLED models like the S90F can provide a cinematic experience in the home living room.

And what about HDR? Here the C6KS performs quite well and – as is becoming the theme of this review – just like in the C6K model. The maximum brightness generated by this television is around 600 nits. In bright scenes, this translates to a really solid, cinematic effect and generally, video materials look good here. However, it's important to keep in mind the specifics of the dimming algorithm in this model. When very small, bright points (e.g. stars) appear on a dark background, the television can quite significantly dim them. The goal is simple: to eliminate blooming and maintain the best possible black. It's a reasonable compromise. Most viewers will definitely appreciate deep, “true black” more than additional microscopic details, the display of which could cause the screen to appear greyed out. Such is the nature of local dimming technology in this price range, and one must be aware of this. It’s also worth noting that the TCL C69KS (C6KS) has an additional PFS coating, which is marketed under the QLED technology slogan. Thanks to this, the colours are saturated and vibrant – our measurements showed that the coverage of a wide colour gamut reaches as much as 92%.

Samsung S90F, like most modern televisions, offers many picture modes, but – following our testing tradition – we checked it out in the best one, which is the Filmmaker mode. Thanks to this, the image looks much more natural than in the default, often oversaturated settings. It was neither overly saturated nor artificially dimmed – simply closer to what one should see. Of course, “more accurate” doesn’t mean “perfect”. Unfortunately, our S90F had significant issues with white balance, particularly in the blue color range, resulting in a slightly yellowish filter being applied to most scenes. Someone might say it looks more “filmic” – because it’s warmer – but let’s not kid ourselves, George Lucas didn’t film Star Wars in sepia 😉 (you’ll find a comparison with the scene below as always).

Additionally, in HDR materials, there was an issue with brightness management. The EOTF curve showed a clear “spike” in brightness – the television brightened the image more than it should have, causing some effects to look too intense and deviating from the reference. Fortunately, some of these problems can be eliminated through professional calibration – you’ll read about its effects later in the review.

In contrast to the more expensive C6K model, in the tested C6KS we don't find an option in the menu labelled as Filmmaker Mode. Is this a reason to cry? Absolutely not. Our tests showed that in practice, in terms of colour reproduction, the lack of this specific label makes virtually no difference. The best available Film/Cinema mode here offers an almost identical picture profile to the aforementioned Filmmaker in the more expensive model. So we get a very similar image, just under a different name. Therefore, if you were wondering whether paying extra for the C6K would give you better colours – the answer is: no, in both cases the base is the same and requires slight adjustments.

After calibration, we managed to eliminate practically all the previously mentioned errors. Older movies in SDR quality finally look like they should – without the sepia effect or artificial aging of the image. The atmosphere of the classics is back in place (no thanks needed, Star Wars fans), and the colours no longer resemble an Instagram filter.

One of the key changes was also the improvement of brightness characteristics in HDR content. We managed to control the EOTF curve in almost a reference manner. Admittedly, the most demanding users may detect minimal deviations in brightness, but honestly – most viewers won't even notice that. And it's no surprise because the vast majority of errors fall below the ΔE 3 value, which is below the threshold of visibility. After calibration, the S90F (WOLED) becomes a truly excellent display – one on which you can enjoy nearly perfect image quality.

Thanks to the white balance adjustment, the C69KS's tendency to distort colours has been effectively limited, leading to a very good final effect. After calibration, we will no longer see excessive warmth in SDR scenes or overly cool tones in HDR. However, it is worth noting the brightness characteristic. In SDR content, there are hardly any objections – the image looks very good, especially in older films, TV shows, or YouTube materials. Evaluating the television's performance in HDR is much more difficult. Analysis of the EOTF curve suggests correct behaviour, but its practical variant shows certain limitations. The C69KS can overly brighten the smallest elements of the frame, while at other times it can dim the entire scene. Calibration has therefore brought clear benefits in terms of colour, but certain limitations resulting from local dimming and the way it is controlled by the C69KS cannot be avoided, which we also observed in the C6K test.

Digital Image Processing in S90F:

Fortunately, Samsung, like in most of its models, manages to effectively tackle the unwanted posterisation effect in the S90F. The function responsible for this element is noise reduction, which does a pretty good job of smoothing tonal transitions and eliminating unnatural colour blending – of course, within its capabilities. Unfortunately, it works quite aggressively, so using it comes with trade-offs. In addition to improving gradation, it can also remove film grain or slightly soften facial features. In this case, the choice is yours – do you prefer a more "clean" image, or do you care about preserving the original texture of the material.

Image Scaling in S90F:

In this year's model, Samsung has implemented its proprietary AI processor – NQ4 Gen3, which really handles upscaling quite well. In our test scenes, the TV effectively "pulled up" lower quality towards artificial 4K – the image was more enjoyable to view, and the differences in sharpness between native and scaled content were minimal. Unfortunately, behind all this AI marketing façade lies a certain shortcoming. The S90F struggles with overscan. If you reach for truly archival material – e.g. a VHS tape of your parents' wedding – you have to reckon with the fact that the lower part of the image may get cut off. The function to adapt the image to resolution simply does not work as it should here.

The C69KS handles upscaling quite well. The tested 576p content looks surprisingly decent – a considerable amount of detail is preserved, and the algorithm adds a subtle ‘rounding’ effect to sharp edges, making the image appear more cohesive. However, it doesn't perform as well when it comes to smoothing tonal transitions. The television practically cannot improve them, leaving the image in a rather raw state. With older materials, this can be simply exhausting, as the lack of additional processing highlights all imperfections.

S90F really handles motion excellently – after all, it’s an OLED with a 144 Hz panel, so sports and games look absolutely stunning on it. The image is smooth, clear, and there’s no room for ghosting or blurring, which can sometimes plague cheaper LCDs.

The TV also comes equipped with motion smoothness settings that allow you to customise everything to your liking. We have motion blur reduction and judder reduction – you can set it so that the image is super smooth (even to the point of looking a bit soap opera-like), or more cinematic, with the classic “jumpiness” of 24 frames. The choice is yours, Samsung imposes nothing.

C69KS offers a simplified motion enhancement panel in movies, allowing users to adjust the intensity of the effect using a slider. This makes it easy to tailor the smoothness to personal preferences. It also deserves credit for the ability to utilise higher refresh rates – even though the panel operates natively in 4K at 60 Hz, by lowering the resolution to 1440p, modes of 120 and 144 Hz can be enabled, on both consoles and PC. This sounds like great news, however, in practice, the image at these settings trails exceptionally badly. The effect is so pronounced that the overall experience simply appears mediocre and loses its appeal in everyday use.

When it comes to gaming features – the S90F has absolutely nothing to complain about. Aside from the lack of Dolby Vision, which is already the norm for Samsung. The television operates at 144 Hz, has four HDMI 2.1 ports, so you can easily connect more than one console or PC. Onboard, we also find Game Bar – a practical tool that allows you to quickly preview picture settings, VRR status, ALLM mode, and other useful options. Game Motion Plus deserves special mention – Samsung's proprietary motion smoother that actually works sensibly in games. The image appears smoother, but without any artificial effects or slowdowns.

It's also worth mentioning the HGiG feature, which – and this may be a slight surprise – works correctly. We bring this up because Samsung clearly messed something up in one of the recent updates, and in some models, the option responsible for HGiG simply... disappears from the menu. Setting it up becomes almost impossible. Fortunately, our S90F unit did not have this issue, but the situation is dynamic, so it's worth keeping this in mind and regularly checking for new software versions and information from the manufacturer.

If we overlook the smudging and lack of native 4K at 120 Hz, the C69KS is impressive in how well it performs for gaming. You get everything you would expect from a gaming TV: Variable Refresh Rate (VRR), Auto Low Latency Mode (ALLM), Dolby Vision Gaming mode, and a consistently functioning HGiG. The TV can also operate at 120 or even 144 Hz at lower resolutions, making gameplay on console or PC smoother. Additionally, there's a clear Game Bar that allows you to quickly check key settings while gaming. As a result — despite a few limitations — the C69KS can be a genuinely successful screen for gamers.