LG OLED C5 vs TCL C9K

LG C5 has finally done what we've been waiting for years in the C series – it exceeds 1000 nits of brightness! This is a significant change compared to previous models in the series and very important – because most HDR content on streaming platforms is created around such luminance today. The image finally has the right "glow," and details in the highlights look as they should even without the use of dynamic metadata. However, there are scenes where the C5, like most OLED TVs, has certain issues. Especially when the screen has to light up entirely. In our test sequences, like the bright scene from the movie The Meg, brightness noticeably drops. Don't get us wrong, this result is not bad; it’s more of a reminder that OLED technology still has its limitations. Year by year, they are getting smaller, but they still exist.

Now, what about the colours? They are very good. Although the C5 doesn't match OLEDs with QD-OLED or Tandem RGB panels, its coverage of the DCI-P3 gamut at 97% and 73% of BT.2020 will satisfy even the more demanding viewers. The colours are saturated, natural, and very consistent in HDR materials.

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.

LG C5, like other TVs we tested, was checked in the best possible factory mode – which remains the Filmmaker Mode. And here we have good news: in SDR materials, LG has once again done a solid job. The white balance and colour reproduction right out of the box are at a very high level. Most errors – both in balance and in the Colour Checker test – did not exceed a ΔE value of 3, which is the threshold above which differences become visible to the naked eye. Such factory settings are what we'd like to see in many more TVs!

However, the situation is different for HDR content, which is what the C series was truly designed for. Here, the C5 performs weaker. An excessive amount of blue in the white balance causes the image to appear distinctly cooler – which affects things like unnaturally pale skin tones or somewhat shifted tonality of the entire scene. Fortunately, LG provides very precise calibration tools, and we – as always – made use of them.

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 must honestly admit – in the case of the LG C5, it took very little to achieve an almost perfect image. After carrying out calibration, we managed to achieve compliance with reference screens at a level that impresses even compared to significantly more expensive models. The image after our adjustments looks exactly as filmmakers and series creators would want – with no colour distortion, natural depth, and subtle plasticity. LG has done a great job this year regarding factory settings and calibration potential. Hats off!

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.

LG C5 handles lower quality materials exceptionally well. One of the main issues that older WOLEDs faced was posterisation – unwanted “steps” in colour transitions. The C5 utilises a system function that smooths these transitions, and it works surprisingly effectively. The banding effect is nearly completely eliminated, and the image gains consistency. Compared to last year's model, we feel that this function operates slightly weaker – but the good news is that it doesn't compromise the image structure. Film grain, textures, and details remain on the screen – nothing is forcefully smoothed out.

The C5 also excels at enhancing the quality of older recordings. Thanks to the α9 Gen6 (8th gen) processor, "scaling to 4K" is impressively solid. The image is clear, details are sharp, and the only minor drawback might be a slightly noticeable aliasing on some edges. However, there is no problem with overscan here – the image is not artificially cropped or shifted, which is a significant plus and still not a given.

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.

The LG C5 is equipped with a 144 Hz display, and this, combined with virtually zero response time of the OLED pixels, makes it one of the best screens for watching dynamic content. It doesn’t matter whether it’s sports, fast-paced games, or just action – the image is razor sharp.

And what about movies at 24 frames? LG has thought of that too. The built-in "TruMotion" smoother allows you to adjust the picture to your own preferences. The “de-judder” slider increases fluidity in films, while “de-blur” subtly reduces motion blur – although to be honest, it’s practically invisible here.

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.

LG C5 is a TV designed with gamers in mind – and there's not a hint of exaggeration in that. It's hard to find anything to criticise here. We have a refresh rate of 144 Hz, full support for VRR, ALLM, and as many as four HDMI 2.1 ports with full bandwidth of 48 Gb/s. For those who have an Xbox, PS5, Nintendo, and a gaming PC in one room – no limitations, everything can be connected without any hassle.

Configuring HDR for gaming is also straightforward. The TV correctly supports the HGiG mode, which allows you to achieve an image that aligns with the creators' intentions. For those interested, there is also Dolby Vision in the Gaming version, although we still recommend HGiG as the most predictable and "clean" variant of HDR in games.

It also includes the Game Bar, which is a "command centre" for the gamer. Everything important, from VRR settings, picture modes, to frame rate information – is at our fingertips. The interface is simple and clear. It may look like something out of a space simulator, but it serves its purpose and just works; exactly as it should.

C5 is truly a complete package for any gamer.

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.