Samsung QD-OLED S90D / S94D vs TCL C9K

In the HDR effect quality category, Samsung S90D achieves remarkable results. On the luminance chart up to 10% window, the TV exceeds the magical threshold of 1000 nits, which is an impressive outcome. However, in the film scenes we tested, these values were slightly lower. Additionally, in the case of a scene with fullscreen sunlight glare, brightness drops to around 500 nits, but it still remains at a very good level. It is worth mentioning that this model stands out with very high colour gamut coverage, thanks to the QD-OLED panel used, which gives it an advantage over TVs with WOLED panels that cannot achieve such a wide spectrum of colours.

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.

Samsung 65 S90D with a QD-OLED panel has been tested in Filmmaker mode, which the manufacturer has been using for years to provide the best possible picture settings. In this mode, the TV offers a fairly decent image but with some shortcomings worth noting. In terms of white balance in HD content, viewers may notice a dominance of the red color. This effect can lead to the impression that certain skin tones appear unnatural and the overall scene will be too warm, which in turn can affect immersion in the watched material. In scenes where subtle differences in color are crucial, these distortions can be particularly noticeable. Similar sensations may also occur in 4K HDR content. Changes in white balance in this case can be analogous, with a noticeably smaller deviation in red color. This can also cause certain details and colors to not be fully represented, making the image lose its naturalness.

When it comes to contrast, the gamma presents quite well, however, some errors are still noticeable. Gamma values are below the reference level of 2.4, which can result in bright areas of the image being washed out and dark areas lacking detail. This limitation can cause some scenes to lack depth and detail, which in turn affects the overall presentation quality. On the other hand, the EOTF curve related to contrast in 4K HDR content performs really well, showing that the TV can effectively convey differences in brightness. Nevertheless, it is worth noting that these values are slightly below the ideal level on the graph, indicating the need for further optimization in this regard.

Samsung S90D in Filmmaker mode offers solid color reproduction, but requires some adjustments to fully realise the potential of the TV, especially in the context of different types of content.

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.

After calibrating the TV, the Samsung S90D in film mode gains quality more than one might expect. The white balance for HD and 4K HDR content has been adjusted to near perfection. Although minor shortcomings can be noticed, they are subtle enough that they don’t significantly impact the overall picture quality. The colours have become more harmonised, aiding in the natural reproduction of details, particularly in scenes that require precise colour representation. It is worth noting that this model, in this size, uses a QD-OLED panel which offers broader colour gamut coverage compared to other sizes of this model that are equipped with a WOLED panel.

The contrast has also significantly improved. After calibration, the gamma graph is much closer to the expected line, providing a better balance between light and dark tones in the picture. The EOTF curve, which before calibration indicated issues with overexposed scenes, now shows significantly better results. This effect allows for the retention of more details in the bright areas of the image, especially in HDR materials.

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.

The television handles tonal transitions excellently, allowing colours to flow smoothly into each other, creating a natural image. The built-in noise reduction feature can further enhance these transitions, which can be useful in certain situations. However, it is worth remembering that activating this option may lead to excessive smoothing of the desired film grain structure, which in turn can affect the authenticity and atmosphere of the image. Therefore, caution is recommended when using this feature to avoid losing the character and depth of the content.

The Samsung S90D model effectively processes materials in lower resolutions. This can be seen in the displayed image. The model's silhouette is clear and naturally reproduced, with details well preserved. Additionally, the branches of the trees are well-defined, showing no visible jagged edges that could degrade the quality of the image. Thanks to effective upscaling, even lower resolution materials look attractive on the screen, which will surely please users enjoying a variety of content sources, such as standard cable or antenna television.

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.

Samsung S90D TV, equipped with a refresh rate panel of 120 Hz, and in the appropriate PC configuration even 144 Hz, ensures excellent motion fluidity. Samsung focuses on a variety of image clarity settings on a ten-point scale, giving users the freedom to adjust the display to their own preferences. In UFO tests, the OLED panel shows its strengths, eliminating any blurring. The lightning-fast pixel response makes dynamic movements faithfully reproduced.

Similar results can be observed in other sizes of this model with a WOLED panel, which also offer excellent image fluidity. Organic technology, in this case, is considered one of the best on the market. The picture of Samsung S90D, regardless of the type of panel, is incredibly sharp and detailed, making this TV perfect for dynamic scenes, both during gaming and sports broadcasts. Additionally, its capabilities in terms of refresh rate and clarity ensure that every movement is smooth and natural, which will certainly satisfy even the most demanding users.

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.

Television S90D is an excellent solution for gamers, offering a range of advanced features that elevate the gaming experience to a new level. Equipped with the HDMI 2.1 standard, the model supports modern technologies such as VRR (Variable Refresh Rate) and ALLM (Auto Low Latency Mode). Thanks to these solutions, the image is incredibly smooth, and the response to commands is instantaneous, which is crucial in dynamic titles. Additionally, the S90D supports HLG (Hybrid Log-Gamma) and G-Sync and FreeSync image synchronisation. This allows for a perfect connection with the Xbox, PlayStation, or PC, eliminating issues with tearing and stuttering. The built-in operating system offers the Xbox Game Pass app, providing access to a massive library of games directly from the television. This solution makes gaming even more convenient and accessible. The Game Bar feature provides quick access to important information, such as current settings, performance statistics, and the ability to adjust image options. This allows for on-the-fly modification of display parameters, which is incredibly useful during intense gameplay. Despite lacking support for Dolby Vision, Samsung S90D still delivers excellent HDR image quality, allowing for full utilisation of the potential of games and films. As a result, S90D represents a unique combination of modern technologies, excellent image quality, and intuitive features, perfect for any gaming enthusiast.

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.