Samsung S90H (WOLED) vs LG OLED C6H (TANDEM OLED)

The Samsung S90H in the WOLED variant is still an exceptionally bright TV for its price bracket, although it is slightly dimmer compared with the QD-OLED version. That difference is not as pronounced as in last year’s F series, where gaps sometimes reached 500 nits. Here the parameters of both panels are very similar, with differences in peak brightness of only about 100–150 nits. In small-window measurements the S90H with the WOLED panel easily reaches close to 1,500 nits. That headroom lets it phenomenally convey the dynamics of HDR effects — blooms, light reflections and explosions have the right punch, exactly as intended by the studio creators. As with most OLED displays, when a very bright scene fills the entire screen, panel protection systems kick in and brightness naturally falls to around 700 nits. It’s worth stressing that this is still an excellent result on the market, often noticeably better than many Mini LED screens in the same segment.

Colour gamut coverage

The biggest difference between the two S90H variants lies in colour reproduction and saturation. This stems directly from the different construction of the WOLED panel, which uses an additional white subpixel. As a result, very high-brightness colours don’t achieve quite the same saturation, and the wide-colour volume is slightly more limited than with QD-OLED. That said, in everyday use these differences will be hard for most viewers to notice. Our measured DCI-P3 coverage on the WOLED panel reaches almost 99%, meaning that for the vast majority of real film scenes both variants will present an almost identical image. The real gap only appears in rarer, especially demanding productions that use the ultra-wide BT.2020 gamut. Because of the WOLED panel’s construction, coverage of that standard is roughly 15% lower compared with the S90HAT with a QD-OLED panel, so the brightest, heavily lit HDR colours may appear a touch less vivid.

And the biggest advantage of the Tandem OLED panel is most obvious with HDR. The C6H's brightness is simply very high and, in our measurements across most film scenes, hovered around 1,900 to 2,300 nits. That's the kind of level at which bright highlights, the sun or small light sources can look truly spectacular. The scene that impressed us most was the fifth scene from the film The Meg. It's particularly demanding for OLEDs because almost the entire screen is extremely bright. Even so, the C6H reached about 1,650 nits in that scene. By comparison, the standard C6 with a classic WOLED panel managed roughly 600 to 700 nits at the same point. So we're talking about more than double the brightness, and in places the difference approaches three times as much. And that's probably the best example of what Tandem OLED delivers. It's not just a higher score on a small test window. The C6H can maintain very high brightness even when much more of the screen is illuminated. That gives HDR a much wider dynamic range, and in this respect the C6H is considerably closer to flagship OLEDs than to typical mid-range models.

Colours

Tandem OLED also brings improvements in colour. DCI-P3 coverage remains virtually complete at around 99%, while in the much wider BT.2020 colour space we measured about 82–83%. That's roughly 7 percentage points more than the standard C6. In everyday viewing this won't be a difference you notice in every scene, because most films don't use such a wide palette. However, when very highly saturated colours appear, the C6H has noticeably greater capability, especially with reds. Reds benefit the most, becoming deeper and more saturated. It's still not at the level of the best QD-OLED panels or SQD TVs, but for a WOLED panel the result is really very good.

In Filmmaker mode, which we strongly recommend switching on straight out of the box, the S90H offers very good factory colour tuning. Colours are natural and faithful to the creators' intent, without the annoying oversaturation seen in more aggressive profiles. However, as is often the case without full calibration, there is unit-to-unit variation. In our test the white balance was a little deficient in the blue component, so the image leaned slightly towards warmer, yellowish tones. This was most noticeable in bright scenes, such as the snowy sequences from Star Wars. Additionally, the gamma curve was slightly low at around 2.2, which caused a small lift in shadow detail. In HDR mode the tuning was a bit better, showing only a slight undersaturation in the red region.

Right out of the box the LG C6 is pretty well set up, especially if you select Filmmaker mode. In SDR content the white balance is good, although as brightness increases it starts to lack red slightly. This makes the picture a bit cooler, but not enough to be very noticeable during normal viewing. More is going on in the luminance response. Gamma is a bit low and instead of holding at 2.4 it sits closer to 2.1–2.2 across a large part of the range. In practice the C6 slightly brightens midtones. Shadows are therefore more readable, but the image loses a little depth compared with how it should look in a dark room.

In HDR the situation is a bit more interesting. The start of the grayscale looks very good, but from around 20–30% brightness the white balance starts to drift more strongly. As brightness increases red builds up and blue becomes noticeably lacking. In the brightest parts the difference is already significant and also affects the reproduction of some colours. The EOTF curve itself is handled quite well across most of the range. The C6 only has a tendency to slightly brighten the picture, which we've already seen in our film comparisons. The biggest deviation appears around the brightest sections where the TV starts to adapt the signal to the panel's capabilities.

So the factory Filmmaker setting in HDR is not perfect, but overall performs well. The biggest room for improvement is the white balance, especially at high brightness.

After full calibration, you can safely say the S90H in the WOLED version looks almost perfect. In SDR mode colour errors fall to ultra-low levels and Delta E values very rarely exceed 2. That's a phenomenal result, so if perfectly faithful colour reproduction matters to you, it's definitely worth getting it calibrated. The calibrated HDR mode also performs very well, where the white balance was stabilised and previous deviations eliminated. After professional tuning it's really hard to fault anything, because the TV delivers an image with almost exemplary naturalness and three-dimensionality. The slightly lower score in this category compared with the QD-OLED variant is solely due to the saturation limitation in extremely bright scenes, while the tuning potential and colour fidelity are at the highest level.

LG TVs have long responded very well to calibration, and the C6 is no exception. After adjustment, the white balance was set almost perfectly, and most colour errors fell to values below 3, often around 2. In practice this means very accurate colour reproduction in both SDR and HDR. An interesting detail only showed up with the HDR luminance response. On a classic EOTF chart everything looks almost perfect and at first glance it would be hard to fault. Only when we measured the TV’s behaviour using filters based on real film scenes did it emerge that the C6 has a slight tendency to artificially boost image brightness.

It isn’t a huge difference and many people may even see it as a positive, since HDR looks a bit more punchy. From the point of view of fidelity to the source material it’s not ideal, though — some scenes are simply a touch brighter than the filmmaker intended. Interestingly, this is quite atypical for LG. In previous generations, this brand’s TVs usually stuck very closely to the reference picture characteristics after calibration. With the C6 we’re still very close to the standard, but that subtle boost in brightness can indeed be noticed in movies and TV shows.

When it comes to banding reduction itself, Samsung has kept the same solutions known from last year’s models. The dedicated gradient-smoothing function works quite well and can effectively mask unwanted tonal transitions, which can be useful on a WOLED panel that’s somewhat more prone to banding. However, it’s important to remember it acts aggressively. This mechanism, aside from the artefacts themselves, can remove fine film grain and subtly soften detail. Ultimately it’s a trade-off, but if you want perfectly faithful image reproduction, it’s safer to leave this option off.

There’s also no breakthrough in scaling. The S90H uses the same NQ4 Gen3 processor as its predecessor, so upscaling quality was almost identical. The chip sharpens lower-resolution material very well, pulling a satisfying level of detail out of it. However, Samsung still hasn’t solved the old overscan problem. For some older recordings or archival footage the edges of the image can be slightly cropped. It’s a minor drawback, but it’s a shame the manufacturer still hasn’t fixed it.

Here the LG C6 has taken a really big step forward. The TV uses the same processor found in the flagship G6, and in terms of image processing the two models are very similar. That's a big plus, because in this area LG's processor this year performs excellently. The 'Smooth Gradation' function works especially well. With heavily compressed material it can effectively hide unsightly tonal banding and artefacts that often appear, for example, in lower-quality streaming. It's best left on the 'Low' setting. That way the improvement is clear, and the TV doesn't yet start to blur fine details. Higher levels smooth the picture more, but can begin to remove some of the natural texture of objects on screen. Upscaling itself also performs very well. Lower-resolution content is properly sharpened, edges look clean, and the processor quite effectively reconstructs fine details. In this respect the C6 is already really close to LG's top TVs and the differences compared with the G6 are small.

When it comes to motion handling the S90H is simply excellent. This year's panel offers its refresh rate boosted to 165 Hz, although in practice the benefit will mainly be for gamers connecting a powerful PC. For movies, TV series or sports broadcasts such a high refresh rate makes no difference and the picture looks exactly the same as at the standard 120 Hz. Regardless of the source, the OLED panel's lightning-fast response time does the job. Motion is clean, and the ghosting or smearing seen on LCDs simply doesn't occur here.

The C6H with a Tandem OLED panel can also run at a refresh rate of up to 165 Hz. PC gamers will get the most out of that, of course, because with consoles, films or sport we're still looking at a maximum of 120 Hz. The panel itself performs excellently in motion. OLED pixels respond almost instantly, so even with fast-moving objects you don't see the usual trailing. The picture stays clean both when watching sport and in fast-paced games.

If you prioritise smoothness over motion clarity, TruMotion is available. LG lets you adjust two parameters separately. De-Judder mainly works with films and series shot at 24 fps and reduces their characteristic judder. De-Blur is intended for 50/60 fps content, so it's mainly useful when watching sport or TV.

Gamers should feel right at home with the S90H, because Samsung has left few reasons to complain in this area. The TV has four HDMI 2.1 ports, each supporting VRR, ALLM and high refresh rates. There's also the Game Bar, a handy menu that lets you quickly check key parameters and change settings without leaving the game. Importantly, Samsung has also improved HGiG. In last year's models it could cause issues when used with a console, but on the S90H it now works as it should. What really stands out against the competition is Game Motion Plus. It's a specialised motion-smoothing mode for games that works best with titles running at 30 or 60 frames per second. Motion becomes noticeably smoother and latency remains at a reasonable level. In our measurements it was under 50 ms, so gaming is still comfortable. That's important, because on many TVs enabling a similar smoothing feature causes such a big increase in input lag that controls become noticeably sluggish. Samsung has managed to find a good compromise here. There's still no Dolby Vision Gaming, but in practice Game Motion Plus may prove to be the more useful feature.

The C6H offers virtually a full gaming feature set. On consoles you can easily use 4K at 120 Hz, while PC users can push the refresh rate up to 165 Hz. The TV also supports VRR from 40 to 165 Hz, ALLM and a correct implementation of HGiG. Dolby Vision is available in game mode too, which remains a big plus for Xbox owners. All the key info can be seen in the Game Bar, which provides quick access to VRR settings and the current signal parameters. The tandem OLED doesn’t change the actual feature set for gamers, but with such high panel brightness HDR games can look even more impressive. Functionally, the C6H is simply a very complete TV for consoles and PC.