SAMSUNG OLED S90F (WOLED) vs TCL C6KS / C69KS / Q6CS

Does the S90F handle not only dark scenes but also bright parts of the image? Definitely yes. Stories about OLEDs as "dark screens" can slowly be regarded as a myth. The Samsung S90F, similar to the LG C5 based on a very similar panel, achieves brightness exceeding 1000 nits. This is a value entirely sufficient to enjoy impressive and dynamic HDR images – both in movies and series. Most of the scenes we tested look stunning, with well-defined lights and high contrast. Of course, OLED technology still has its limitations – with very bright, full-screen sequences, such as the test card from the movie The Meg (5th image), the TV can noticeably dim the image. However, it's worth noting that such scenes are quite rare. One can say that the HDR effect is good enough that even mid-range OLED models, like the S90F, can provide a cinematic experience in the home living room.

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.

Samsung S90F, like most modern TVs, offers many picture modes, but – in line with our testing tradition – we checked it in its best one, which is the Filmmaker mode. As a result, the image looks much more natural than in the default, often oversaturated settings. It was neither overly saturated nor artificially subdued – just closer to what you should see. Of course, "more correct" doesn’t mean "perfect." Our S90F sample unfortunately had significant issues with white balance, particularly in the blue color range, resulting in a slightly yellowish filter applied to most scenes. Someone might say that it looks more "cinematic" – because it's warmer – but let's be honest, George Lucas didn't film Star Wars in sepia 😉 (you'll find the comparison with the scene as always below).

Additionally, in HDR materials, there was a noticeable issue with brightness management. The EOTF curve showed a distinct "spike" in brightness – the TV brightened the image more than it should have, making some effects look too intense and diverging from the reference. Thankfully, some of these issues can be eliminated with professional calibration – you can read about its effects later in the review.

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, we managed to eliminate almost all the aforementioned errors. Older movies in SDR quality finally look as they should – without the sepia effect or artificial aging of the image. The atmosphere of the classics is returning to its rightful place (you're welcome, Star Wars fans), and the colors no longer resemble an Instagram filter.

One of the key changes was also the improvement of brightness characteristics in HDR content. We managed to control the EOTF curve in an almost reference way. Yes, the most demanding users may notice minimal deviations in brightness, but to be honest – most viewers won't even notice that. And it’s no wonder, because the vast majority of errors are below the ΔE 3 threshold, which is below the visibility threshold. After calibration, the S90F (WOLED) becomes a truly excellent display – one that you can enjoy nearly perfect image quality on.

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.

Digital image processing in the S90F:

Fortunately, Samsung, as in most of its models, can effectively deal with the unwanted posterization effect in the S90F. The function responsible for this element is noise reduction, which quite nicely smooths out tonal transitions and eliminates unnatural color joins – of course, within its capabilities. Unfortunately, it works quite aggressively, so using it comes with compromises. In addition to improving gradation, it may also remove film grain or gently soften facial features. In this case, the choice is yours – do you prefer a more "clean" image, or do you care about preserving the original texture of the material.

Image scaling in the S90F:

In this year's model, Samsung has implemented its own AI processor – NQ4 Gen3, which really manages quite well with upscaling. In our test scenes, the television effectively "pulled up" lower-quality content towards artificial 4K – the image was more pleasant to view, and the differences in sharpness between native and scaled content were minimal. Unfortunately, behind this entire AI marketing façade lies a certain shortcoming. The S90F does not handle overscan well. If you reach for truly archival materials – like a VHS tape of your parents' wedding – you must reckon with the fact that the lower part of the image may be cut off. The image adaptation function to the resolution simply does not work here as it should.

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.

S90F really handles motion great – after all, it's an OLED with a 144 Hz panel, so sports and games look simply amazing on it. The picture is smooth, clear, and there's no room for ghosting or blurring that sometimes plagues cheaper LCDs.

The TV is also equipped with motion smoothing settings that allow you to tailor everything to your liking. We have motion blur reduction and judder reduction – you can set it up to make the picture super smooth (even to that soap opera effect), or more cinematic, with the classic "choppiness" of 24 frames. The choice is yours; Samsung doesn't impose anything.

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.

When it comes to gaming features – we have absolutely no complaints about the S90F. Aside from the lack of Dolby Vision, which is already the norm for Samsung. The TV operates at 144 Hz, has four HDMI 2.1 ports, so you can easily connect more than one console or PC. It also includes Game Bar – a practical tool that allows you to quickly preview picture settings, VRR status, ALLM mode, and other useful options. Game Motion Plus is also noteworthy – Samsung’s proprietary motion smoother, which uniquely works well in games. The image feels smoother without any artificial effects or slowdowns.

It’s also worth mentioning the HGiG feature, which – surprisingly – works correctly. We mention this because Samsung clearly broke something in one of its recent updates, and in some models, the option responsible for HGiG simply... disappears from the menu. Setting it becomes virtually impossible. Fortunately, our S90F unit did not have this issue, but the situation is dynamic, so it’s worth keeping this in mind and regularly checking for new software versions and information from the manufacturer.

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.