Samsung QD-OLED S90D / S94D vs TCL C9K

In the HDR effect category, the Samsung S90D delivers remarkable performance. On the luminance graph for up to 10% of the window, the television surpasses the 1000 nits mark, which is a notable achievement. However, in the film scenes we tested, these values were slightly lower. In scenes with fullscreen sun glare the brightness drops to about 500 nits, but this is still considered a very good result. It is also worth noting that this model stands out due to its very high colour gamut coverage, thanks to the QD-OLED panel, giving it an edge over televisions with WOLED panels, which cannot achieve such a wide spectrum of colours.

As we mentioned with black and contrast – the C9K makes a huge impression in synthetic tests. Our measurements showed that on a screen 10% filled with white, the television is capable of squeezing out... 4000 nits of brightness! It sounds cosmic, but – and here unfortunately the pattern repeats – the numbers say one thing, and practice another. In real film scenes, the situation looks different. In the best case, when the light effects occupy a large part of the image and the local dimming algorithm doesn't have to think too hard about what to do with thousands of zones – the result is really quite good. At that point, the C9K can reach about 1500 nits, which provides a pleasant, intense flash and can indeed make a positive impression.

The problem begins 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 even to 400–500 nits. This is a huge difference compared to the potential of 4000 nits that we saw in laboratory tests. Why does this happen? Most likely, the television tries to protect the black and minimise the halo effect around bright objects. Unfortunately, this comes at the cost of details – some of the intricate details simply disappear, and the scene loses its nature.

The Samsung 65" S90D with a QD-OLED panel has been tested in Filmmaker Mode, which the manufacturer has used for years to deliver optimal picture settings. In this mode, the TV offers a very good image, but there are some shortcomings worth noting.

In terms of white balance, viewers may notice a red dominance in HD content, which can make skin tones appear unnatural and create a warm overall scene, potentially affecting immersion. This issue becomes more apparent in scenes where subtle colour differences are important. The same effect can be observed in 4K HDR content, though the red shift is less pronounced. This shift can prevent certain details and colours from being fully realised, diminishing the naturalness of the image.

As for contrast, the gamma performance is decent but still has some issues. The gamma values fall short of the reference level of 2.4, resulting in bright areas of the image appearing washed out and dark areas lacking detail. This limitation can make certain scenes feel less dynamic and impact the depth and richness of the picture. However, the EOTF curve for contrast in 4K HDR content performs well, showing the TV's ability to handle differences in brightness. That said, these values still fall slightly below the ideal range, indicating room for further optimisation.

Overall, the Samsung S90D in Filmmaker Mode offers solid colour reproduction, but some adjustments are needed to fully unlock its potential, particularly with different types of content.

For colour tests, we once again reached for the Filmmaker mode – a new feature in TCL televisions for 2025. And although the direction itself is a step in the right direction, the execution leaves much to be desired. The white balance in SDR content turned out to be too warm – there was an excess of red. Conversely, 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 – managing brightness. Regardless of whether we were watching SDR or HDR content, the image had a tendency to blow out the entire scene, giving it an unnatural, almost grotesque character. Therefore, it is hard to call this a 'director’s mode' – because the director surely has never seen such an image.

The quality improves more than anticipated after calibrating the S90D television in movie mode. The white balance for HD and 4K HDR content has been fine-tuned to near perfection. While minor imperfections are still noticeable, they are subtle enough not to significantly impact the overall picture quality. Colours have become more cohesive, promoting a natural reproduction of details, particularly in scenes where precise colour representation is essential. It’s important to note that this particular model, in this size, uses a QD-OLED panel, which offers a broader colour gamut compared to other versions of this model equipped with a WOLED panel.

The contrast has also seen a marked improvement. After calibration, the gamma chart is much closer to the expected curve, resulting in a better balance between the bright and dark areas of the image. The EOTF curve, which previously indicated issues with overexposed scenes, now shows significantly better results. This improvement allows for greater preservation of details in the brighter parts of the image, particularly in HDR content.

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 with 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 managing brightness was also brought under control in SDR content, and the effect was more than satisfactory. Unfortunately, when we switched on the HDR material, the situation quickly became complicated. No matter how we set the local dimming, the television had a tendency to do what it pleased with the image – either overexposing the whole picture or dimming the darkest parts too much. Just like we saw in the scene from the film Billy Lynn. Colour-wise, the improvement after calibration makes a great impression, but managing brightness in HDR remains the Achilles' heel of the C9K and constitutes a technological limitation.

The television excels at smoothing tonal transitions, allowing colours to blend seamlessly, resulting in a natural and fluid image. The built-in noise reduction feature can further enhance these transitions, useful in certain situations. However, it is important to note that activating this option may overly smooth out the desired film grain structure, potentially compromising the authenticity and atmosphere of the image. Therefore, caution is advised when using this feature, to maintain the character and depth of the content.

The S90D model handles lower-resolution materials effectively, as demonstrated in the displayed image. The model's silhouette remains sharp and naturally reproduced, with fine details preserved. Additionally, the branches of the trees are well-defined, free from any visible jagged edges that might otherwise degrade the image quality. Thanks to efficient scaling, even lower-resolution content appears attractive on the screen, which is sure to please users who rely on a variety of content sources, such as standard cable or antenna television.

The digital image processing in TCL C9K is rather mediocre. The tone transition smoothing feature is supposedly present, but activating it hardly makes any difference – colour banding is still visible, and it can inadvertently highlight elements we would prefer to hide, such as textures of objects. Fortunately, it does not remove film grain, but that's scant consolation considering the effects are still poor. Thus, it's hard to recommend using this option.

On the other hand, image scaling performs significantly better. Lower quality materials look quite decent – characters and backgrounds are represented clearly, although of course, with sources like 576p, the limitations of the physics cannot be disguised. Sometimes, there's characteristic aliasing of objects, but that's due to the source itself, not the algorithm. A plus for the fact that there are no overscan issues – the image is neither artificially cropped nor enlarged.

The S90D TV, featuring a 120 Hz refresh rate matrix and up to 144 Hz in the appropriate PC configuration, delivers excellent motion fluidity. Samsung highlights a range of sharpness settings on a ten-point scale, allowing users to fine-tune the display to their preferences. In UFO tests, the OLED matrix showcases its strengths by eliminating any blurring. The ultra-fast pixel response ensures dynamic movements are faithfully reproduced.

Similar results can be seen in other sizes of this model with a WOLED matrix, which also offer outstanding image fluidity. Organic technology, in this case, is considered among the best on the market. The S90D image, regardless of the matrix type, is exceptionally sharp and detailed, making this television perfect for dynamic scenes, whether for gaming or sports broadcasts. Additionally, its refresh rate and sharpness capabilities guarantee that every movement is smooth and natural, satisfying even the most discerning users.

Similar to the C8K, the C9K is also a really fast television – both figuratively and literally. On board, we have 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 picture looks very smooth and clear. Additionally, in films, we get an extra motion smoothing feature called Motion Clarity, which allows you to adjust the smoothness to your own preferences – from the cinematic "stuttering" of frames to nearly theatrical smoothness.

The S90D television is an excellent solution for gamers, offering a range of advanced features that elevate gaming quality to a new level. Equipped with 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) as well as G-Sync and FreeSync image synchronisation. This enables a perfect connection with 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 vast library of games directly from the television. This solution makes gaming even more convenient and accessible. The Game Bar feature provides quick access to essential information, such as current settings, performance statistics, and the ability to adjust image options. This allows for on-the-fly display parameter modification, which is extremely useful during intense gameplay. Despite lacking support for Dolby Vision, the S90D still offers excellent HDR image quality, allowing for full utilization of the potential of games and movies. As a result, the S90D represents a unique combination of modern technologies, outstanding image quality, and intuitive features, perfect for any gaming enthusiast.

For gaming, the TCL C9K is a complete tool. Here we have two (out of four) HDMI 2.1 ports with full bandwidth of 48 Gbps, 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, which allows you to quickly check the most important parameters and adjust settings without rummaging through the menu. Also worth noting is TCL's policy – the television does not shy away from 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 a wide range of freedom.