TCL C9K vs LG OLED G6 (G64LW, G66LS)

As we mentioned regarding black levels and contrast – the C9K can make a huge impression in synthetic tests. Our measurements showed that on a screen 10% filled with white, the television can achieve... 4000 nits of brightness! It sounds out of this world, but – and here's where the pattern unfortunately repeats – the numbers say one thing, and the practical experience says another. In real movie scenes, the situation looks different. In the best-case scenario, when light effects occupy a large part of the image and the local dimming algorithm doesn't have to ponder too much about what to do with thousands of zones, the effect is really quite good. At that point, the C9K can hit around 1500 nits, which delivers a pleasant, intense burst and can indeed leave a positive impression.

The problem arises with smaller elements – such as stars in the sky, the moon, or individual reflections. That's when the proverbial cat comes out of the bag: the algorithms are not yet refined, and brightness drops to as low as 400–500 nits. That's a huge difference from the potential 4000 nits we saw in lab tests. Why does this happen? Most likely, the television is trying to protect the black levels in this way and minimize the halo effect around bright objects. Unfortunately, this comes at the expense of detail – some details simply vanish, and the scene loses its nature.

The LG G6 is currently one of the brightest OLEDs on the market. Its peak brightness reaches nearly 2500 nits and, best of all, this translates directly to real movie scenes. The TV flawlessly extracts details in the bright areas of the image. And this is regardless of whether we are talking about very small points in the form of stars in the sky or slightly larger elements on the screen. Naturally, with full-screen, uniformly white scenes, the brightness of the G6 drops due to the panel protection system (ABL). However, in real, varied movie shots, this value still hovers around an impressive 2000 nits, which can be considered a remarkable result. The coverage of the color palette also deserves praise. The new 2nd generation Tandem OLED panel has brought about only a cosmetic change, but still an improvement. The coverage of the DCI-P3 color space reaches nearly 99.5%, while the ultra-wide BT.2020 is around 84%. These are very good results, although it's important to remember one thing: at extremely high brightness levels, the volume of colors will be lower than in QD-OLED panels from Samsung Display due to the use of white sub-pixels (WOLED). However, in everyday content and most films, capturing this difference will be very difficult.

For colour tests, we once again reached for the Filmmaker mode – a new feature in TCL televisions for 2025. While the direction is a step in the right way, the execution leaves a lot to be desired. The white balance in SDR content turned out to be too warm – there was an excess of red. On the other hand, in HDR, it swung in the opposite direction: the image became excessively blue. The Colour Checker test revealed quite a few colour inaccuracies that were noticeable to the naked eye. An even bigger problem turned out to be what we mentioned above – brightness management. Regardless of whether we were watching SDR or HDR content, the image tended to wash out the entire scene, giving it an unnatural, almost grotesque character. Therefore, it’s hard to call this a "director's mode" – because no director has ever seen such an image.

We tested the LG G6 in the best factory mode for colour fidelity, which is FILMMAKER MODE. In the case of our test unit, this mode was reasonably well tuned straight out of the box. In SDR content, the only issue we noticed was the white balance, which leaned towards warmer tones. This made the image occasionally appear slightly yellowish, but overall, it wasn't a significant problem. The G6 performed a bit worse in HDR content. There, the white balance showed too much blue component. This caused the image to veer towards cooler shades, resulting in quite noticeable errors. As can be seen on our ColorChecker chart, the colours shifted towards these cooler registers. Nevertheless, considering the factory settings, the television presented a perfectly decent level. However, we know that OLED screens – particularly those from LG – respond exceptionally well to professional calibration, so we immediately proceeded to do just that.

After calibration, we finally managed to tame the white balance – and it immediately translated into a more natural image. Colours finally started to look as they should, and the overall presentation was incomparably better than on the factory settings. In other words – it’s worth taking a moment to improve this, as the gain is really significant. The gamma responsible for brightness management also managed to be brought into order in SDR content, and the effect was more than satisfactory. Unfortunately, when we turned on HDR materials, the situation quickly became complicated. No matter how we set the local dimming, the television had a tendency to do what it liked with the image – either it overexposed everything or darkened the darkest parts too much. Just like we saw in the scene from the movie Billy Lynn. Colour-wise, the improvement after calibration makes a great impression, but brightness management in HDR remains the Achilles' heel of the C9K and presents a certain technological limitation.

After completing a professional calibration, we gained complete control over the panel, and we managed to align all parameters to nearly zero. We were able to tune the white balance perfectly, which removed the factory's cool and warm tints from the screen. The effects are visibly clear in the ColorChecker test – the average colour reproduction errors dropped below the critical value of 1-2. And what does this mean? PERFECT colours, without any distortion! However, as a reviewer’s duty, we must point out how the LG G6 arbitrarily manipulates brightness, which is due to the EOTF curve's behavior. When we look at the standard synthetic graph, it might seem that the line is quite straight. However, the situation changes when we turn on the measurement filter, which shows how the television interprets brightness in actual, moving film scenes (EOTF in MOVIES). Then, it is clear as day that some of the smallest fragments on the screen are slightly overly brightened by the algorithm. Of course, for the average viewer, such a deviation will practically go unnoticed, but in the test of such an expensive screen, it’s worth noting – especially since we are talking about a model that has huge aspirations for the title of the best television of the year.

Digital image processing on the TCL C9K is rather average. The smooth tone transition feature seems to be present, but activating it practically changes nothing – colour bands are still visible, and it can unintentionally highlight elements we’d rather keep hidden, such as object textures. Fortunately, it doesn’t remove film grain, but that’s poor consolation given that the effects are still meagre. It’s therefore hard to recommend using this option.

On the other hand, image scaling presents itself much better. Lower quality materials look quite decent – characters and backgrounds are rendered clearly, although of course, with sources like 576p, the laws of physics cannot be fooled. Occasionally, there’s characteristic edge distortion of objects, but that’s the fault of the source itself, not the algorithm. A plus for not having issues with overscan – the image isn't artificially cropped or enlarged.

No matter what one might say about the G6's issues with near-black signal, it must be fairly acknowledged that it handles heavily compressed material and lower resolution content extremely well. All unwanted, ugly tonal transitions are effectively reduced here by the "Smooth Gradation" feature. At the "Low" setting, the algorithm works flawlessly – effectively masking the artifacts resulting from strong compression without destroying the sharpness and details in the frame. Higher levels of this feature do further smooth the image, but they start to blur the real texture elements of the objects, so we recommend keeping this slider at a low level. As for the actual upscaling to 4K, the processor does an excellent job – edge sharpness and detail reconstruction are at the highest level, and in this respect, the G6 is on par with the global leaders.

Similar to the C8K, the C9K is also a really fast TV – both figuratively and literally. It features a 4K panel with a refresh rate of 144 Hz, and at lower resolutions, the panel can even ramp up to 288 Hz. Such speed translates into practice – while watching sports or playing games, the image looks very smooth and clear. Additionally, in movies, we get an extra motion smoother called Motion Clarity, which allows you to adjust the smoothness to your own preferences – from cinematic "judder" to almost theatrical smoothness.

The LG G6 is an OLED television, so in the category of motion fluidity, it traditionally deserves the highest marks. The TV supports very high refresh rates of up to 165 Hz in 4K resolution, but most importantly – there are absolutely no signs of blurring on the screen. The response time of the matrix is virtually instant, ensuring that dynamic images remain perfectly sharp.

From a gaming perspective, the TCL C9K is a complete tool. It features two (out of four) full bandwidth 48 Gbps HDMI 2.1 ports, so all the key technologies work: VRR (Variable Refresh Rate) and ALLM (Auto Low Latency Mode). Additionally, the manufacturer has included a really intuitive Game Bar that allows you to quickly check the most important parameters and adjust settings without fumbling through menus. Also, TCL's policy is a plus – the TV isn’t afraid of any HDR formats, even in game mode. Whether it's HGiG or Dolby Vision for the Xbox Series S/X console – everything works as it should, giving the player plenty of freedom.

The LG G6 is a true beast for gamers and one of the best-equipped TVs on the market in this regard. The manufacturer didn't compromise and equipped this model with four full HDMI 2.1 ports with a maximum bandwidth of 48 Gbps. This means that no matter which port you plug in your PlayStation 5, Xbox Series X, or powerful PC, you'll get the absolute maximum performance out of them.

The TV supports a full suite of gaming technologies: from VRR (Variable Refresh Rate), to AMD FreeSync Premium Pro, and Nvidia G-Sync Compatible. Let's add to that a remarkably low, almost imperceptible input lag and an excellently functioning game panel (Game Optimizer), which allows you to constantly monitor signal parameters. Gaming on this screen, with the perfect black of OLED and powerful refresh rates, is pure pleasure.