Samsung OLED S90F (QD-OLED) vs TCL C6KS / C69KS / Q6CS

The biggest difference between the 65-inch S90F and the other versions is brightness. The QD-OLED panel can reach up to 1700 nits in laboratory tests, which is over 500 nits more than the version with a WOLED matrix. This translates to a significantly stronger and more immersive HDR effect. In most scenes, the bright parts of the image look stunning, and we must admit that we were positively surprised, as we expected results closer to the WOLED version, but what we got is an effect that impresses even in films. As with every OLED, there are moments when the panel must reduce brightness a bit. This mainly concerns full-screen, very demanding scenes – for instance, in the last test scene from the movie “The Meg,” brightness drops to around 800 nits. However, it's hard to consider this a flaw because it's still an excellent result, unprecedented in OLED TVs in this price range. Everything suggests that the 65-inch S90F could be one of the best choices this year for those looking for a strong OLED at a reasonable price. Another advantage of the QD-OLED matrix in HDR content is its colour gamut coverage. Thanks to quantum dots, the television achieves nearly 100% of the DCI-P3 gamut and almost 90% of the BT.2020 gamut. These are values that place it alongside much more expensive models and make it exceptional in its class.

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 several picture modes, but in keeping with our tradition, we checked it in the most important one, which is Filmmaker. This setting makes the picture look much more natural than in the default, often oversaturated modes. It is neither overly vivid nor artificially dimmed – just closer to what you should actually see. However, this doesn’t mean it’s perfect. The S90F had noticeable shortcomings in white balance, particularly in the blue range, which created a slightly yellowish filter effect on most scenes. One might argue that it looks more “cinematic” because it’s warmer, but let’s not kid ourselves – George Lucas didn’t shoot Star Wars in sepia 😉 (you’ll find a comparison with a scene as always below). In HDR materials, there was also an issue with brightness management. The EOTF curve clearly showed that the television brightens the image more than it should, which led to some effects looking too intense and deviating from the reference. Fortunately, many of these flaws can be eliminated through professional calibration – we will discuss the effects of this procedure later in the test.

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.

Calibration quickly revealed that the S90F has a significant reserve of capabilities. The image in SDR immediately gained a natural quality – classic films no longer looked like someone was applying a yellowish filter, and the colours regained their proper character. It's a return to the atmosphere of the original, without the impression that someone tried to "age" it forcefully. In HDR content, the difference was even more pronounced. The EOTF curve was managed to nearly reference level, and any deviations are so subtle that most viewers wouldn't even notice them. In practice, the S90F shows an image very close to ideal post-calibration. Compared to the WOLED version, it even performs better – mainly due to a wider coverage of the colour palette, which makes the colours look fuller and more vibrant.

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.

S90F performs really well here, although there are some points that are common across most Samsung TVs. The noise reduction feature can effectively smooth out unwanted colour transitions in lower-quality materials like television or YouTube, making them look simply better. However, it should be noted that it works quite aggressively and can also soften elements that we wouldn’t want to alter, such as facial details. Therefore, if we want to use it, it’s best to use it in the "medium" setting and be aware of the compromise it brings. The upscaling itself is of a high standard – low-quality materials are pulled towards an image resembling 4K. The only caveat is that the S90F can still have issues with so-called overscan, meaning slight trimming of the edges in very low-quality materials such as 576p and lower.

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 is an OLED with a refresh rate of 144 Hz, but in practice, what matters most is how it performs at 120 Hz, as this frequency is the most important when watching sports. The QD-OLED panel is no different in this regard from WOLED panels – the pixel response is nearly instantaneous, so motion is rendered with surgical precision. The effect is easy to predict. The image is practically free of motion blur, making gaming on consoles, matches, or other sports broadcasts a tremendous pleasure on the S90F.

Fans of movies and series have not been forgotten either. Like every Samsung television with a refresh rate of 120 Hz and above, the S90F is equipped with a proprietary motion smoother called “Picture Clarity.” Here, we find two sliders – blur reduction and judder reduction – which allow you to improve the smoothness of content recorded at 24 frames and tailor the effect to your own preferences.

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.

The S90F is a television that genuinely brings a lot of joy when gaming. To start with, we get four proper HDMI 2.1 ports, which means you can connect all consoles and PCs without having to figure out which device takes priority. This is a convenient and practical solution, which is not at all a given with other manufacturers. Additionally, there are key features such as: automatic game mode (ALLM), which automatically switches the screen to low latency settings, and VRR frame synchronization that operates over a wide range from 48 to 144 Hz. This ensures the picture remains smooth, whether we're playing fast-paced online shooters or more relaxed narrative titles. The Game Bar also deserves attention – a panel that allows quick access to several handy extras. For example, you can turn on an extra crosshair in the middle of the screen, enlarge the minimap, or, in the case of PC, change the aspect ratio. Finally, there's also Samsung's unique Game Motion Plus mode. Its task is to smooth out older or poorly optimized titles, and it actually works quite well. With this mode, even less polished games can look better and provide more enjoyment than on other televisions that theoretically offer the same technical parameters.

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.