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

Does the S90F handle not only black, but also bright parts of the image? Definitely yes. Tales of OLEDs as “dark screens” can slowly be regarded as a myth. The Samsung S90F, like the LG C5 based on a very similar panel, achieves brightness exceeding 1000 nits. This is a value entirely sufficient to enjoy impressive and dynamic HDR imagery – both in films and series. Most of the scenes we tested look superb, 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 pattern from the film The Meg (picture 5), the television may noticeably dim the image. However, it should be emphasized that such scenes are rare. It can be considered 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 has become a recurring theme of this review – identically to 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, the video materials look good here. However, one must keep in mind the specifics of the dimming algorithm in this model. When very small, bright points (e.g., stars) appear against a dark background, the television can dim them quite significantly. The goal is simple: to eliminate blooming and maintain the best possible blacks. This is quite a reasonable compromise. Most viewers will definitely appreciate deep, "true black" more than additional micro-details, the display of which could cause the screen to appear greyed out. This is the nature of local dimming technology in this price range, and one must be aware of it. It is also worth noting that the TCL C69KS (C6KS) has an additional PFS coating, which is marketed under the slogan of QLED technology. 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% here.

The Samsung S90F, like most modern televisions, offers many picture modes, but – in line with our testing tradition – we assessed it in the best one, which is the Filmmaker mode. This way, the image looks significantly more natural than in the default, often oversaturated settings. It was neither overly saturated nor artificially muted – just closer to what should be seen. Of course, "more correct" does not mean "ideal". Unfortunately, our S90F unit had considerable issues with white balance, especially in the blue range, resulting in a slightly yellowish filter being applied to most scenes. Someone might say it looks more "cinematic" – because it is warmer – but let's not kid ourselves, George Lucas did not film Star Wars in sepia 😉 (you will find the comparison with the scene as always below).

Additionally, in HDR materials, there was a noticeable issue with brightness management. The EOTF curve showed a clear "spike" in brightness – the television brightened the image more than it should have, which made some effects look overly intense and diverged from the reference. Fortunately, some of these problems can be eliminated through professional calibration – you will read about its effects later in the review.

Unlike the more expensive C6K model, the tested C6KS does not have an option in the menu labelled as Filmmaker Mode. Is this a reason to cry? Absolutely not. Our tests have shown 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 characteristic 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 gives 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 films in SDR quality finally look as they should – without the sepia effect or artificial aging of the image. The atmosphere of the classics returns to its rightful place (you’re welcome, 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. Yes, the most demanding users may spot minimal deviations in brightness, but honestly – most viewers won’t even notice that. And it's no wonder, because the vast majority of errors are below a ΔE value of 3, which is below the threshold of visibility. After calibration, the S90F (WOLED) truly becomes an excellent display – one that provides nearly perfect picture quality.

Thanks to the white balance adjustment, the C69KS's tendency to distort colours has been effectively limited, resulting in a very good final effect. After calibration, we will no longer see excessive warming of scenes in SDR or overly cool tones in HDR. However, it is worth noting the brightness characteristics. In SDR content, it is hard to have any objections – the image looks very good, especially in older films, television programmes, or materials from YouTube. It is significantly more challenging to evaluate the television's performance in HDR. Analysis of the EOTF curve suggests correct behaviour, but its practical variant reveals certain limitations. The C69KS can overly brighten the smallest elements of the frame, while at other times, it can dim the entire scene. Thus, calibration brought clear benefits in terms of colour quality, but certain limitations resulting from the local dimming operation and the way it is controlled by the C69KS cannot be overlooked, as we also saw in the C6K test.

Digital Image Processing in the S90F:

Fortunately, Samsung, as in most of its models, effectively manages the unwanted posterisation effect in the S90F. The feature responsible for this aspect is noise reduction, which does a decent job of smoothing tonal transitions and eliminating unnatural colour connections – of course, within its limitations. Unfortunately, it operates rather aggressively, so using it comes with compromises. In addition to improving gradation, it can also remove film grain or gently soften facial features. In this case, the choice is yours – do you prefer a more "clean" image, or do you want to preserve the original texture of the material?

Image Scaling in the S90F:

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

The C69KS handles upscaling quite well. The tested 576p material looks surprisingly decent – a considerable amount of detail is retained, and the algorithm adds a slight "rounding" effect to sharp edges, making the image appear more cohesive. The performance in smoothing tonal transitions is less impressive. The television practically cannot improve them, leaving the image in a rather raw state. With older material, this can be quite tiring, as the lack of additional processing highlights any imperfections.

The 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 fluid, clear, and there’s no room for any ghosting or blurring that sometimes plagues cheaper LCDs.

The television is also equipped with motion smoothness settings, allowing you to customise everything to your preference. We have motion blur reduction and judder reduction – you can set it so that the image is super smooth (even to that soap opera effect), or more cinematic, with the classic 24-frame 'choppiness'. The choice is yours; Samsung doesn’t impose anything.

C69KS offers a simplified motion enhancement panel in films, allowing the adjustment of effect intensity with a slider. This makes it easy to match fluidity to personal preferences. The ability to use higher refresh rates is also a plus – although the panel operates natively at 4K at 60 Hz, lowering the resolution to 1440p enables 120 and 144 Hz modes, both on consoles and PC. This sounds like great news, however, in practice, the image at these settings exhibits significant motion blur. The effect is so pronounced that the overall presentation appears merely average and loses its appeal for everyday use.

When it comes to gaming features – the S90F has absolutely nothing to fault. 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 the Game Bar – a practical tool that allows you to quickly glance at picture settings, VRR status, ALLM mode, and other useful options. Game Motion Plus also deserves a mention – Samsung's proprietary motion enhancer that is the only one truly functioning sensibly in games. The image appears smoother, but without any artificial effects or slowdowns.

It is also worth mentioning the HGiG feature, which – much to our slight surprise – works correctly. We're mentioning this because Samsung clearly broke something in one of the last updates, and in some models, the option responsible for HGiG simply... disappears from the menu. Setting it up becomes practically 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 updates and information from the manufacturer.

If we overlook the smudging and lack of native 4K at 120 Hz, the C69KS impresses with how well it performs during gaming. We get everything one can expect from a gaming television: variable refresh rate (VRR), automatic switching to game mode (ALLM), Dolby Vision Gaming mode, and a well-functioning HGiG. The television can also operate at 120 and even 144 Hz at lower resolutions, allowing for smoother gameplay on a console or PC. Additionally, there is a clear Game Bar that lets you quickly glance at key settings while gaming. As a result — despite a few limitations — the C69KS can be a really successful screen for gamers.