Samsung S90H (QD-OLED) vs LG OLED C6H (TANDEM OLED)

The Samsung S90H is a really bright TV for the mid-range among OLEDs. In synthetic measurements its peak brightness reached around 1650 nits. That's an outstanding result in this class, roughly 50% higher than what we’ve seen from previous models at this price point. Most importantly, these tests translate directly to real video material. In four out of the five film scenes we tested the S90H’s brightness hovered around 1300-1500 nits. That kind of headroom lets it reproduce most HDR films with very high impact and without obvious compromises, especially material mastered to 1000–1500 nits. In practice, highlights, reflections and explosions have the right punch and the picture doesn’t feel dimmed. Of course, on full-screen, very bright scenes the result is naturally lower and drops to about 900 nits. That’s a direct effect of the protection systems that keep the OLED panel from being overloaded. Even in that scenario there’s little to complain about. Nine hundred nits across the whole screen is still a very high level, guaranteeing excellent dynamics in HDR content. A huge advantage of QD-OLED TVs has always been the colours, and the S90H is no exception. The DCI-P3 colour space we measured reached a full 100% (actually 99.9%), while coverage of the much wider BT.2020 gamut hit about 89%. That’s a great result, allowing very saturated and vivid colours in HDR material. It’s worth emphasising that QD-OLED’s edge over WOLED panels isn’t just about gamut coverage. In practice it’s seen mostly in the higher brightness of saturated colours, in other words greater colour volume. That makes intense reds, greens and blues in HDR look juicier and more impressive.

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.

The next stage of the test was to check how the S90H handles colour reproduction without any calibration. As always, we took measurements in Filmmaker Mode, the best factory picture setting. And here Samsung really deserves praise. The factory tuning is at a very high level, which wasn’t always the case a few years ago. The white balance was set correctly, as was the brightness response. The average colour reproduction error (Delta E) stayed around 3, which is below the level at which most viewers can notice inaccuracies. Only in the brightest shades of grey did the values slightly approach 4, but it’s still hard to call that a real problem during viewing. For out-of-the-box settings, the result is simply excellent.

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.

All right, but you know we wouldn't be ourselves if we didn't also check how much we could get out of the S90H with professional calibration. And there was no big surprise. Since the out-of-the-box settings were already very good, there wasn't a huge margin for improvement. Even so, we managed to refine the image almost to perfection. After calibration the average colour reproduction errors fell below the threshold of perception, reaching Delta E values under 2 for both SDR and HDR material. We also improved the luminance response, so the picture more faithfully reflects the creators' intent and maintains correct tonality across the entire brightness range. After professional calibration the S90H therefore becomes a screen very close to reference. Will the difference be spectacular for everyone? Not necessarily. The factory settings already deliver a very high level, so in everyday viewing some people may not notice a huge jump. Much also depends on the specific unit. Our sample was very well tuned straight out of the box, but that doesn't mean every S90H will present the same level. Even identical models can differ in their factory calibration. That's exactly why professional calibration makes sense: it lets you bring a particular unit to the highest possible accuracy, rather than relying on a bit of luck when buying.

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.

W tej kwestii Samsung praktycznie nic nie zmienił względem ubiegłorocznego modelu, co akurat jest dość dobrą wiadomością. Funkcja odpowiedzialna za wygładzanie przejść tonalnych nadal bardzo skutecznie ogranicza efekt posteryzacji. Trzeba jednak pamiętać, że działa dość agresywnie, bo oprócz samych artefaktów potrafi usunąć również ziarno filmowe i delikatnie zmiękczyć drobne detale obrazu. Jak zwykle jest to więc kwestia kompromisu i własnych preferencji. Jeśli zależy Wam na jak najwierniejszym odwzorowaniu materiału, polecamy pozostawić tę funkcję wyłączoną.

Również w kwestii upscalingu trudno mówić o rewolucji. S90H korzysta z tego samego autorskiego procesora obrazu NQ4 Gen3 co jego poprzednik, dlatego jakość skalowania pozostała praktycznie bez zmian. Telewizor dobrze radzi sobie z materiałami o niższej rozdzielczości, skutecznie poprawiając ich ostrość. Nadal jednak nie rozwiązano problemu z overscanem. W przypadku niektórych starszych materiałów, zwłaszcza archiwalnych nagrań, może zdarzyć się, że fragment obrazu przy krawędziach zostanie ucięty. To drobna wada, ale szkoda, że Samsung kolejny rok z rzędu pozostawił ten problem bez zmian.

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.

In terms of motion handling the S90H delivers a very high level of performance. A new feature here is a panel with a refresh rate of up to 165 Hz, although in practice this will mainly benefit PC gamers. Movies, TV series and sports broadcasts don’t use such high refresh rates, so when watching them the difference compared with the standard 120 Hz won’t be noticeable. That said, thanks to the OLED panel’s instantaneous response time, motion is very clean and the image doesn’t suffer from the smearing common to many LCDs. Samsung has equipped the TV with extensive motion settings. You get two sliders: judder reduction and blur reduction, which let you easily tailor the image’s character to your preferences. You can easily achieve very smooth motion for sport, but you can just as easily preserve a more cinematic feel at the typical 24 fps. It all comes down to which effect you prefer.

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.

From the start, the Samsung S90H gives the impression of a TV designed with gamers in mind, and it's easy to see why. The maker has equipped it with nearly everything you’d expect from a modern gaming display. You get as many as four full-bandwidth HDMI 2.1 ports, support for ALLM, VRR and very high refresh rates. There's also a clear Game Bar that lets you quickly check key picture parameters or change settings without leaving the game. Another very welcome improvement is HGiG support. Last year it could cause quite a few problems, but in the S90H it works exactly as it should.

Samsung's real ace, however, is its proprietary Game Motion Plus mode. The feature works much like the motion smoothing used in films: it improves animation smoothness in games while keeping input lag at a very reasonable level. For titles running at 30 or 60 fps, with the right settings, input lag in our testing never exceeded 40 ms. That's an excellent result, especially since on many manufacturers' TVs enabling similar features results in delays several times higher. Game Motion Plus doesn't replace Dolby Vision Gaming, of course, since it's a completely different type of feature, but overall for gaming it's an addition that many players may find more noticeable. Smoother motion in 30/60 fps games often makes more of a difference than HDR itself, which, incidentally, is often poorly implemented in games.

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.