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

Samsung S90H in the WOLED variant is still an exceptionally bright TV for its price bracket, although compared with the QD-OLED version it is slightly dimmer. The difference is not as significant as in last year’s F series, where the gap could reach as much as 500 nits. Here the parameters of both panels are very similar, and differences in peak brightness are only in the order of 100–150 nits. In small-area measurements the S90H on the WOLED panel easily reaches levels close to 1500 nits. Such a reserve of power allows HDR dynamics to be reproduced phenomenally; all highlights, light reflections and explosions have the necessary punch, exactly as the creators intended in the editing studio. As with most OLED displays, when a very bright scene fills the whole screen protection systems activate and brightness naturally falls to around 700 nits. It is worth emphasising 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 results directly from the different construction of the WOLED panel, which uses an additional white subpixel. As a consequence, colours at very high brightness do not reach the same intense saturation, and the volume of the wide gamut is somewhat more limited than in QD-OLED. That does not change the fact that in everyday use these differences will be hard for most viewers to spot. The DCI-P3 space we measured reaches nearly 99% on the WOLED panel, which means that in the vast majority of real film scenes both variants will present an almost identical picture. The true distance only reveals itself in rarer, exceptionally demanding productions that use the ultra-wide BT.2020 gamut. Due to the specifics of the WOLED panel’s construction, coverage of that standard is about 15% lower compared with the S90HAT with a QD-OLED panel, so the brightest, heavily lit colours in HDR may appear slightly less vivid.

And it is with HDR that the Tandem OLED panel shows its greatest advantage. The C6H’s brightness is simply very high and in our measurements it hovered around 1900–2300 nits in most film scenes. That’s already a level at which bright highlights, the sun or small light sources can look truly spectacular. The biggest impression, however, was made by the fifth scene from the film The Meg. It is exceptionally demanding for OLEDs because almost the entire screen is very bright. Even so, the C6H reached about 1650 nits in that scene. By comparison, the regular C6 with a classic WOLED panel recorded around 600–700 nits at the same point. So we’re talking about more than double the brightness, and in places the difference even approaches three times. And that is probably the best example of what Tandem OLED delivers here. It’s not just a higher result on a small test patch. The C6H can maintain very high brightness even when much more of the screen is lit. As a result HDR has significantly greater dynamism, and in this respect the C6H is much closer to flagship OLEDs than to typical mid-range models.

Colours

Tandem OLED also brings an improvement in colours. DCI-P3 coverage remains practically complete at about 99%, while in the much wider BT.2020 colour space we measured around 82–83%. That’s roughly seven percentage points more than the regular C6. In everyday use this won’t be a difference visible in every scene, because most films do not use such a wide gamut. However, when very highly saturated colours appear, the C6H already has noticeably greater capability, especially in reds. Reds benefit the most, becoming deeper and more saturated. This still isn’t at the level of the best QD-OLED panels or SQD TVs, but for a WOLED panel the performance 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 irritating oversaturation found in more aggressive presets. However, as is often the case without full calibration, no two units are identical. In our test the white balance was slightly lacking in blue, causing the image to lean a little 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 2.2, which produced a minor lift in shadow detail. In HDR mode the tuning was somewhat better, showing only a slight undersaturation in the red region.

Straight out of the box the LG C6 is fairly well set up, especially if you select the Filmmaker mode. In SDR content the white balance is decent, although as brightness increases it shows a slight deficiency in red. The image therefore becomes a little cooler, but not enough for the difference to be very noticeable during normal viewing. More is happening in the brightness response. Gamma is a bit low and, instead of holding at 2.4, it sits closer to 2.1–2.2 across much of the range. In practice the C6 slightly brightens midtones. Shadow detail is therefore more readable, but the picture loses some depth compared with how it should look in a darkened room.

In HDR the situation is a bit more interesting. The lower end of the greyscale performs very well, but from roughly 20–30% brightness the white balance starts to drift increasingly. As brightness rises there is more red, while blue becomes noticeably deficient. In the brightest scenes the difference is already substantial and also affects the reproduction of some colours. The EOTF itself is, however, fairly well tracked across most of the range. The C6 merely tends to slightly brighten the image, which we already saw in our film comparisons. The largest deviation appears in the very brightest areas, where the TV begins to adapt the signal to the panel’s capabilities.

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

After a full calibration it’s fair to say the S90H in WOLED guise looks almost perfect. In SDR mode colour inaccuracies drop to ultra-low levels and Delta E values very rarely exceed 2. That’s a phenomenal result, so if you care about perfectly faithful colour reproduction it’s definitely worth considering calibration. The calibrated HDR mode also performs very well, with the white balance stabilised and earlier deviations eliminated. After professional fine-tuning it’s really hard to find anything to criticise, because the TV delivers an image with almost reference-level naturalness and three-dimensionality. The slightly lower score in this category compared with the QD-OLED variant is solely due to the aforementioned limitation in saturation in extremely bright scenes; the tuning options and colour fidelity themselves are at the highest level.

LG TVs have long been very receptive to calibration and the C6 is no exception. After adjustment the white balance could be set almost perfectly, and most colour errors fell below 3, often even down to around 2. In practice this means very accurate colour reproduction in both SDR and HDR. An interesting detail only emerged when we looked at the HDR luminance response. On a classic EOTF plot everything looks almost ideal and at first glance it would be hard to find fault. Only when we measured the TV's behaviour on filters based on real film scenes did it become apparent that the C6 has a slight tendency to artificially boost image brightness.

It is not a huge difference and many people may even welcome it because HDR looks a bit more striking as a result. From the point of view of fidelity to the source material this is not ideal behaviour though – some scenes are simply a touch brighter than the filmmaker intended. Interestingly, this is rather unusual for LG. In previous generations the brand's TVs typically stuck closely to the reference picture characteristic after calibration. With the C6 we are still very close to the standard, but this subtle brightness 'boost' can indeed be noticed in films and series.

In terms of posterisation reduction itself, Samsung has kept the solutions known from last year’s models. The dedicated gradient-smoothing function performs quite well and can effectively mask unwanted tonal banding, which is useful on a WOLED panel that is slightly more prone to banding. However, you should be aware of its aggressive behaviour. This mechanism, alongside the artefacts themselves, can clean up fine film grain and gently soften detail. Ultimately it is a matter of compromise, but if you want an absolutely faithful reproduction, it is safer to leave this option off.

Similarly, in the area of scaling it is difficult to call this a breakthrough. The S90H uses the same NQ4 Gen3 processor as its predecessor, so the upscaling quality was almost identical. The chip sharpens lower-resolution material very well, extracting a satisfying level of detail. Samsung still has not dealt with the longstanding overscan issue, though. With some older recordings or archive footage the edges of the image can be slightly cropped. It’s a minor flaw, but it’s a pity the manufacturer still hasn’t eliminated 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 considerable plus, because this year's LG processor excels in that area. The "Smooth Gradation" function works particularly well. With heavily compressed footage it can effectively hide ugly banding and artefacts that often occur, for instance in lower-quality streaming. It's best to leave it on the "Low" setting. Then the improvement is noticeable, while the TV does not yet start to blur fine detail. Higher levels smooth the picture more, but can already remove some of the natural texture of objects on screen. Upscaling itself also performs very well. Lower-resolution material is sharpened correctly, edges look clean, and the processor quite effectively reconstructs fine detail. In this respect the C6 is already very close to LG's best TVs and the differences compared with the G6 are small.

In terms of motion handling, the S90H is simply excellent. This year's panel offers a boosted refresh rate of up to 165 Hz, though in practice the benefit will mainly be for gamers connecting a high-end PC. For films, 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, however, the OLED panel's lightning-fast response time does its job, so motion is clean and the ghosting or smearing familiar from LCD screens simply does not occur here.

The C6H with a Tandem OLED panel can also operate at refresh rates of up to 165 Hz. PC gamers will naturally get the most out of this, because for consoles, films or sport we're still looking at a maximum of 120 Hz. The panel itself is excellent when it comes to motion. OLED pixels respond virtually instantly, so even with fast-moving objects you don't see the typical motion blur. The picture remains clean whether you're watching sport or playing 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 helps reduce the judder that's characteristic of them. De-Blur, meanwhile, is intended for 50/60 fps content, so it's particularly useful when watching sport or television.

Players should feel at home with the S90H, because Samsung has left few reasons to complain in that respect. The TV has four HDMI 2.1 ports, each of which supports 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 mode. In last year’s models it could cause problems when used with a console, but on the S90H it now works as it should. What really stands out against the competition is the Game Motion Plus feature. It’s a special motion smoothing mode for games that works best with titles running at 30 or 60 fps. Motion becomes noticeably smoother, while 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 large 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 a much more useful feature.

The C6H offers practically the full suite of gaming features. 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 proper implementation of HGiG. Dolby Vision is also available in game mode, which remains a major advantage for Xbox owners. All key information can be viewed in the Game Bar, which provides quick access to VRR settings and the current signal’s parameters. The OLED implementation therefore does not alter the feature set available to gamers, but with such high panel brightness HDR games can make an even stronger impression. Functionally, the C6H is simply a very complete TV for console and PC gaming.