TCL RM7L vs LG OLED B6

TCL RM7L is a bright TV. In our measurements its peak brightness hovered around 1600 nits. That is clearly less than the C7L, which can approach 2600 nits, but in real film scenes the difference between the models is not that large. In less demanding shots with many bright elements, the RM7L can sustain about 1000 nits, and sometimes even a little more, getting close to 1500 nits. It performs worse in dark scenes with small points of light, where their brightness can fall to around 500 nits. This is not random behaviour. The TV intentionally dims fine details to better control the backlight and preserve higher contrast. That comes at the expense of their intensity, but it is typical behaviour for TVs with local dimming in a similar price bracket.

Colour gamut coverage

In HDR not only brightness matters but also colour. And here the RM7L has plenty to show. Colours are highly saturated and a wide colour gamut is one of its major strengths. In our DCI-P3 measurements it reached about 96%, and BT.2020 around 83%. It is worth remembering that on a TV with this kind of backlight the result can vary depending on the scene. On test patterns colours look best, while in films their saturation is sometimes a little lower than on SQD Mini LED or QD-OLED TVs. The construction of the backlight itself is also interesting. The RM7L does not use the classic red, green and blue LED set. TCL used two green LEDs and one blue, with the red produced by a PFS phosphor. This shows up in spectrometer measurements, but it does not have a major impact on the picture. Colours are still rendered correctly.

The LG B6 is a moderately bright OLED. After calibration it reaches around 800 nits, roughly 200 nits more than last year’s B5. That’s down to the new, budget OLED SE panel from LG Display. In practice it simply gives a bit more headroom and makes HDR look fuller in many scenes than on last year’s lower‑end OLEDs. That does not mean the B6 has no limitations. In very bright shots, when a large part of the screen is strongly lit, brightness can fall below 400 nits. This behaviour is typical for OLED TVs, especially in this segment, and that’s where you see the biggest difference compared with more expensive models. Even so, we judge the B6’s results as genuinely solid. It’s still not a TV for breaking brightness records, but the HDR effect is strong enough that films truly feel like a step up from ordinary SDR. Colour gamut Using the OLED SE panel has had a slight impact on wide colour gamut coverage. Compared with last year’s model the results have fallen by a few percentage points. It covers roughly 96% of DCI‑P3 and about 71% of BT.2020. That doesn’t mean the colours on the LG B6 are weak. In most films and series they look lively, well saturated and simply pleasing to the eye. You only notice the difference in very bright, highly colourful scenes. Then colours lose some intensity compared with QD‑OLED panels. This stems from the WOLED panel structure. Besides red, green and blue subpixels it also uses a white subpixel, which helps to boost brightness. However, this comes at a price. At very high luminance some colour is effectively 'diluted' by the white light, so the saturation of certain colours can be slightly lower. In everyday use this isn’t a major issue, but in the most demanding scenes you can notice it.

We checked the out-of-the-box colours in Filmmaker Mode, the best picture setting available to the user. TCL has been using it in its TVs for two years, and its aim is to reproduce the image as faithfully as possible in line with the creators' intent. On the RM7L it was indeed the most accurately set mode, although it was not without flaws. The biggest problem was the white balance. Too much red and blue made the image shift towards slightly pink tones. This was visible in both SDR and HDR. On top of that the brightness response was slightly boosted, making the picture appear a little brighter but at the same time less contrasty than it should be.

We tested the LG B6 in Filmmaker Mode, the best picture setting available straight out of the box. ISF modes produce very similar results, but in our tests we always stick to Filmmaker Mode for better comparison with other TVs. Each of them is, in any case, a much better starting point than Vivid or Eco mode, where the picture is heavily boosted and noticeably less natural. On SDR material the factory settings perform really well. Colour errors are small, the gamma response is correct, and the picture during normal viewing looks natural and does not feel overly "pumped up". It's a bit worse with HDR. When such content is played you quickly see that the white balance hasn't been set perfectly. Too much blue and red gives the image a slightly pink tint. This is also confirmed by colour gamut measurements and the ColorChecker, where samples clearly shift in that direction. It's not a flaw that completely spoils the picture, but it is noticeable with HDR films. Therefore anyone who wants the most faithful image should consider calibration, which we cover further on in the review.

Thanks to the fairly extensive calibration menu we were able to correct the vast majority of the previously described issues. The biggest change concerned the white balance. After calibration it now looks very good, so the picture shed its pinkish tint and became much more neutral. The luminance response has also improved. Both the SDR gamma and the HDR EOTF curve are now much closer to the reference values. The picture is no longer unnecessarily brightened, and darker areas look more natural and have greater depth. Better luminance accuracy also affected the colours, which after calibration are noticeably more accurate. Not everything could, however, be set perfectly. With HDR material the RM7L still interprets part of the signal in its own way and does not always follow the reference curve precisely. This is most apparent in some darker scenes, where the TV can either slightly lift the shadows or darken them completely. That is where the earlier impression of a slightly brightened, less contrasty picture came from. Despite this, the calibration delivers a very good result. It removes the most visible errors and, above all, makes the picture much closer to how it should look.

During calibration, we concentrated mainly on HDR content, because that's where the factory settings needed the most correction. We did not, however, neglect SDR mode, which after adjustment was brought almost to perfection. Colours are very accurate, and brightness is controlled as it should be. The biggest improvement in HDR came from fixing the white balance. Removing the excess red and blue eliminated the pinkish tint, and the image became much more natural. Skin tones, whites and all colours that had previously shifted towards pink improved. After calibration most errors fell below a Delta E of 2–3, the threshold at which the average viewer stops noticing differences with the naked eye. So the LG B6 can deliver a very accurate picture, particularly for the manufacturer's entry-level OLED model.

Upscaling and digital image processing are not the RM7L's strong suit. TCL has used the MediaTek Pentonic 700 chipset here, designated MT5896, which is not among the best processors when it comes to handling lower-quality source material. The biggest problems appear with heavily compressed content from YouTube or standard broadcast TV. The processor cannot effectively hide posterization and the characteristic banding between tones. The feature intended to smooth these issues does little to help, and can also interfere with the image too much, smoothing, for example, faces or fine textures. For that reason it is best simply not to use it.

Standard upscaling to 4K looks better. Lower-quality content is sufficiently sharp and retains an adequate amount of detail. It is not on a par with the best processors on the market, but for everyday viewing the result is entirely acceptable.

The LG B6 handles lower-quality material very well. This is largely thanks to effective digital image processing, which can mask some of the source’s imperfections without overly smoothing the whole scene. The "Smooth Gradation" function proves particularly useful. It noticeably reduces posterisation, especially in dark parts of the image. The safest choice remains the Low or Medium setting. The function still effectively smooths out unsightly tonal banding, but does not yet interfere too much with fine details. Purists can of course leave it switched off. Upscaling to 4K also performs very well. Full HD and 720p material retain a good amount of detail, and the image is neither overly sharpened nor heavily blurred. Some limitations only become apparent with very poor sources below 720p, where the smallest text and fine elements are not always perfectly sharp, but this applies to almost every other TV on the market.

The RM7L features a 144 Hz VA panel, so from the outset it is well suited to sports, gaming and other fast-paced content. The high refresh rate also gives the motion interpolation more scope, allowing it to generate additional frames. On the RM7L it works well and, with the right settings, can noticeably improve motion smoothness without an excessive soap opera effect.

One of the biggest advantages of OLED panels is the very fast pixel response time. This keeps the picture sharp and free of the visible smearing often seen on LCD TVs. However, there is a downside. During slow camera pans motion can look choppier than on LCD screens, where some of that effect is naturally masked by the slower panel. Fortunately, on the LG B6 this can be easily mitigated using the TruMotion system. With the motion smoothing set correctly you can achieve smoother motion without giving the picture an exaggerated soap opera effect.

The RM7L earns almost nothing but praise when it comes to features for gamers. The TV supports ALLM, VRR and Dolby Vision Gaming and works properly with HGiG, so it’s hard to point to any major omissions in that regard. In practice this means automatic switching to a low-latency mode, smoother motion at variable frame rates and accurate brightness reproduction in HDR games. There’s also a very useful Game Bar. From it you can quickly check frame rate, VRR status, signal format or aspect ratio, and change the key settings without leaving the game. TCL has also added a few extra options, such as a crosshair overlay and brightening of dark image areas, which can be handy in some titles. The biggest drawback stems from the use of the Pentonic 700 processor. Only two of the four HDMI ports support the full HDMI 2.1 standard. That won’t matter much with a single console, but if you connect two consoles and a PC you may run out of ports, especially since one of those ports may be needed for eARC and a soundbar.

LG OLED B6 has plenty to offer gamers; it’s simply a complete base for PS5, Xbox Series X/S or a capable PC. It has four full-size HDMI 2.1 ports with 48 Gbps bandwidth, so you can avoid irritating cable swapping when connecting several newer devices at once. It offers a full suite of synchronization technologies, from standard VRR to G-Sync and FreeSync. The screen synchronises the refresh rate seamlessly with the frame output from the console or graphics card. Of course it includes ALLM: the B6 automatically recognises when a game is running and immediately reduces latency to a minimum. HDR support is also excellent. The TV supports Dolby Vision, and a correctly implemented HGiG standard means that, after initial calibration in the console settings, the image won’t suffer from blown-out highlights or lost detail in bright areas. The cherry on the cake is the Game Bar. Instead of digging through the full menu during gameplay, a single click is enough to adjust shadow visibility, tweak selected parameters or simply check the current display mode. All of this makes the LG B6 an excellent choice for gamers.