TCL C9K vs Samsung OLED S90F (QD-OLED)

As we mentioned regarding black levels and contrast – the C9K can make a huge impression in synthetic tests. Our measurements showed that on a screen 10% filled with white, the television can achieve... 4000 nits of brightness! It sounds out of this world, but – and here's where the pattern unfortunately repeats – the numbers say one thing, and the practical experience says another. In real movie scenes, the situation looks different. In the best-case scenario, when light effects occupy a large part of the image and the local dimming algorithm doesn't have to ponder too much about what to do with thousands of zones, the effect is really quite good. At that point, the C9K can hit around 1500 nits, which delivers a pleasant, intense burst and can indeed leave a positive impression.

The problem arises with smaller elements – such as stars in the sky, the moon, or individual reflections. That's when the proverbial cat comes out of the bag: the algorithms are not yet refined, and brightness drops to as low as 400–500 nits. That's a huge difference from the potential 4000 nits we saw in lab tests. Why does this happen? Most likely, the television is trying to protect the black levels in this way and minimize the halo effect around bright objects. Unfortunately, this comes at the expense of detail – some details simply vanish, and the scene loses its nature.

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.

For colour tests, we once again reached for the Filmmaker mode – a new feature in TCL televisions for 2025. While the direction is a step in the right way, the execution leaves a lot to be desired. The white balance in SDR content turned out to be too warm – there was an excess of red. On the other hand, in HDR, it swung in the opposite direction: the image became excessively blue. The Colour Checker test revealed quite a few colour inaccuracies that were noticeable to the naked eye. An even bigger problem turned out to be what we mentioned above – brightness management. Regardless of whether we were watching SDR or HDR content, the image tended to wash out the entire scene, giving it an unnatural, almost grotesque character. Therefore, it’s hard to call this a "director's mode" – because no director has ever seen such an image.

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.

After calibration, we finally managed to tame the white balance – and it immediately translated into a more natural image. Colours finally started to look as they should, and the overall presentation was incomparably better than on the factory settings. In other words – it’s worth taking a moment to improve this, as the gain is really significant. The gamma responsible for brightness management also managed to be brought into order in SDR content, and the effect was more than satisfactory. Unfortunately, when we turned on HDR materials, the situation quickly became complicated. No matter how we set the local dimming, the television had a tendency to do what it liked with the image – either it overexposed everything or darkened the darkest parts too much. Just like we saw in the scene from the movie Billy Lynn. Colour-wise, the improvement after calibration makes a great impression, but brightness management in HDR remains the Achilles' heel of the C9K and presents a certain technological limitation.

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.

Digital image processing on the TCL C9K is rather average. The smooth tone transition feature seems to be present, but activating it practically changes nothing – colour bands are still visible, and it can unintentionally highlight elements we’d rather keep hidden, such as object textures. Fortunately, it doesn’t remove film grain, but that’s poor consolation given that the effects are still meagre. It’s therefore hard to recommend using this option.

On the other hand, image scaling presents itself much better. Lower quality materials look quite decent – characters and backgrounds are rendered clearly, although of course, with sources like 576p, the laws of physics cannot be fooled. Occasionally, there’s characteristic edge distortion of objects, but that’s the fault of the source itself, not the algorithm. A plus for not having issues with overscan – the image isn't artificially cropped or enlarged.

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.

Similar to the C8K, the C9K is also a really fast TV – both figuratively and literally. It features a 4K panel with a refresh rate of 144 Hz, and at lower resolutions, the panel can even ramp up to 288 Hz. Such speed translates into practice – while watching sports or playing games, the image looks very smooth and clear. Additionally, in movies, we get an extra motion smoother called Motion Clarity, which allows you to adjust the smoothness to your own preferences – from cinematic "judder" to almost theatrical smoothness.

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.

From a gaming perspective, the TCL C9K is a complete tool. It features two (out of four) full bandwidth 48 Gbps HDMI 2.1 ports, so all the key technologies work: VRR (Variable Refresh Rate) and ALLM (Auto Low Latency Mode). Additionally, the manufacturer has included a really intuitive Game Bar that allows you to quickly check the most important parameters and adjust settings without fumbling through menus. Also, TCL's policy is a plus – the TV isn’t afraid of any HDR formats, even in game mode. Whether it's HGiG or Dolby Vision for the Xbox Series S/X console – everything works as it should, giving the player plenty of freedom.

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.