Samsung OLED S90D / S94D (WRGB OLED) vs TCL C6KS / C69KS / Q6CS

The Samsung S90D demonstrates impressive brightness performance in the tested film scenes, surpassing the 1000 nits mark in the first four shots—an outstanding result for an OLED display. In the final shot, which features a fullscreen flash of sunlight, the brightness dips to around 500 nits. While this is a decrease, it remains within a very good range, ensuring visibility and detail retention even in bright scenes.

Another key highlight of the Samsung S90D is its remarkable colour coverage, achieving 98% of the DCI-P3 colour space. This means the TV can reproduce an exceptionally wide range of colours, contributing to vivid and lifelike images that are particularly beneficial for films, high-quality video, and HDR content. The high colour accuracy and impressive brightness capabilities, makes the S90D an ideal choice for users seeking premium image quality across various lighting environments, whether in darker rooms or bright, sunlit spaces.

And how does the issue of HDR look? Here the C6KS performs quite well and – as is becoming a recurring theme in 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 remember 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 black levels. It’s a reasonable compromise. Most viewers will definitely appreciate deep, “true black” more than additional micro-details that could cause grayness on the screen. Such is the nature of local dimming technology in this price range, and one must be aware of it. It’s also worth noting that the TCL C69KS (C6KS) has an additional PFS coating, which is marketed under the tagline of QLED technology. Thanks to this, the colors are saturated and vibrant – our measurements showed that the coverage of a wide color gamut reaches 92% here.

The S90D was tested in Filmmaker mode, which provides good colour reproduction, albeit with some imperfections that may be noticeable to more discerning users. This mode might appear overly warm, and those switching from Standard mode could find the change somewhat jarring. It is important to note that this issue stems from suboptimal settings, such as the white balance, rather than the Filmmaker mode.

In both SDR and HDR content, the device shows a drop in blue tones, resulting in colours appearing warmer than intended. In practice, this means that certain shades, such as sky blue or skin tones, may seem less natural, with a slight pink or yellow tint. The Colour Checker test confirms these deviations, indicating a shift towards warmer hues. In SDR content, the gamma chart reveals slight inconsistencies that make the image appear marginally darker, particularly in shadowed areas, which may obscure finer details in darker scenes.

In 4K HDR content, the EOTF curve exceeds the recommended level, leading to an overly bright display in some parts of the image, which can cause highlights to appear blown out. Overall, the Samsung S90D delivers a solid image straight out of the box, but for the best performance, further calibration is advised, especially with more demanding content.

Unlike the more expensive C6K model, the tested C6KS does not have an option labeled Filmmaker Mode in the menu. Is this a reason to cry? Absolutely not. Our tests have shown that in practice, in terms of color reproduction, the absence of this specific label makes virtually no difference. The best available Film/Cinema mode here offers nearly identical picture characteristics to the aforementioned Filmmaker mode in the more expensive model. So we get a very similar image, just under a different name. So if you were wondering whether paying extra for the C6K gives you better colors – the answer is: no, in both cases the base is the same and requires slight adjustments.

After calibration, the Samsung S90D in movie mode exceeds expectations. The white balance for HD and 4K HDR content has been refined to near perfection. While minor imperfections remain, they are so subtle that they don’t significantly impact the overall image quality. The colours are now more balanced, resulting in a natural reproduction of details, particularly in scenes requiring an accurate colour palette. It’s important to note that this model, in this size, uses a WOLED panel, which has a smaller wide colour gamut coverage and doesn't deliver the same vibrant colours as the 65-inch version with its QD-OLED panel.

The contrast has also seen notable improvements. Following calibration, the gamma curve now closely aligns with the expected line, achieving a better balance between the bright and dark areas of the image. The EOTF curve, which previously exhibited issues with overexposed scenes, now produces more accurate results, allowing for improved detail retention in the brighter parts of the image, especially in HDR content.

Thanks to the white balance adjustment, the tendency of the C69KS to distort colors has been effectively reduced, leading to a very good final effect. After calibration, we won't see excessive warmth in SDR scenes or overly cool tones in HDR. However, it's worth noting the brightness characteristic. In SDR content, there are hardly any objections – the image looks very good, especially in older films, television programs, or materials from YouTube. It is much more difficult to evaluate the performance of the television in HDR. Analysis of the EOTF curve suggests correct behavior, 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 color reproduction, but certain limitations arising from the operation of local dimming and the way it is controlled by the C69KS cannot be avoided, as we also saw in the C6K test.

The S90D TV handles tonal transitions exceptionally well. Thanks to advanced technology, the transitions between colours are smooth and natural. The noise reduction function can further enhance the smoothness of tonal shifts, which is particularly useful in certain situations. However, it's important to note that enabling noise reduction can also blur the natural film grain, diminishing the cinematic quality of the image. For this reason, it’s advisable to use this function with caution, as preserving the natural grain can enhance the character and authenticity of the content being watched.

As always, Samsung excels in image scaling from lower resolutions. The S90D effectively processes lower-resolution content, delivering a clear and accurate picture. The model’s outline is crisp, ensuring the image looks natural and detailed. Even the finer details, such as tree branches, are well-rendered without visible jagged edges that could degrade image quality. Thanks to its effective scaling, the S90D ensures that even lower-resolution content looks appealing, satisfying users who enjoy a wide range of content sources, such as regular broadcast or cable TV.

C69KS handles upscaling quite well. The tested 576p material looks surprisingly decent – a significant amount of detail is preserved, and the algorithm adds a subtle "rounding" effect to sharp edges, making the image appear more cohesive. However, the smoothing of tonal transitions is lacking. The television practically cannot improve them, leaving the image in a somewhat raw state. With older materials, this can be simply exhausting, as the lack of additional processing highlights all imperfections.

The Samsung S90D television features a 120 Hz panel, with the option to "overclock" to 144 Hz when connected to a compatible PC, offering exceptional motion smoothness. Samsung has long provided a range of image sharpness settings on a ten-point scale, allowing users to tailor the display to their preferences. In the UFO test, the OLED panel shows no signs of blurring, with pixel response instantaneous and effectively capturing dynamic movements. OLED technology is renowned for its performance in this regard, making it one of the best options on the market. The image remains incredibly sharp and detailed, even during fast-paced action, making the S90D an excellent choice for gamers and sports enthusiasts alike.

C69KS offers a simplified motion improvement panel in movies, allowing you to adjust the intensity of the effect using a slider. This makes it easy to match the smoothness to your own preferences. The possibility of using higher refresh rates is also a plus – even though the panel operates natively at 4K at 60 Hz, lowering the resolution to 1440p allows you to enable 120 and 144 Hz modes, both on consoles and PC. This sounds like great news, but in practice, the image at these settings suffers from significant motion blur. The effect is noticeable enough that the overall experience feels simply mediocre and loses its appeal in everyday use.

The Samsung S90D is an ideal choice for gamers, featuring four HDMI 2.1 ports that support key gaming technologies such as Auto Low Latency Mode (ALLM), Variable Refresh Rate (VRR), and HDR Gaming Interest Group (HGIG). These features ensure smoother and more responsive gameplay, greatly enhancing performance during intense gaming sessions. The TV also includes a dedicated Game Bar, which makes managing game settings easy. This functionality allows users to quickly adjust parameters like the aspect ratio offering flexibility for different games and gameplay styles. Customising preferences is straightforward, further enhancing the convenience and enjoyment of gaming.

For PC users, the TV impresses by supporting a refresh rate of 144Hz when connected to a computer. Users with Nvidia or AMD graphics cards can also use G-Sync and FreeSync for a smoother gaming experience. However, it’s important to note that the TV does not support Dolby Vision, which may be a drawback for some. That said, Dolby Vision is not as widely adopted in gaming as in film, so this may not be a significant concern for most gamers. Overall, the S90D offers exceptional features for gamers, making it an excellent choice for those seeking outstanding image quality and modern technological solutions.

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