LG OLED G4 vs TCL C9K

LG G4 guarantees an incredibly vivid HDR effect, placing the television among the very best. The equipment of the highest model in the producer's 2024 portfolio with the second generation of micro-lens technology (MLA) has achieved a maximum brightness level of 1474 nits in real scenes. The only area where the product from the Korean manufacturer may lag behind LCD televisions with Mini LED backlighting is during the full-screen scenes featuring a lot of white. If we disregard the latter type of scene, the average result would be even higher. It is also worth mentioning scenes with very fine details, where each one shines at full intensity, which is not as evident in non-OLED televisions. The combination of such brightness and wide coverage of the DCI-P3 palette makes HDR materials more engaging than ever before.

As we mentioned with black and contrast – the C9K makes a huge impression in synthetic tests. Our measurements showed that on a screen 10% filled with white, the television is capable of squeezing out... 4000 nits of brightness! It sounds cosmic, but – and here unfortunately the pattern repeats – the numbers say one thing, and practice another. In real film scenes, the situation looks different. In the best case, when the light effects occupy a large part of the image and the local dimming algorithm doesn't have to think too hard about what to do with thousands of zones – the result is really quite good. At that point, the C9K can reach about 1500 nits, which provides a pleasant, intense flash and can indeed make a positive impression.

The problem begins 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 even to 400–500 nits. This is a huge difference compared to the potential of 4000 nits that we saw in laboratory tests. Why does this happen? Most likely, the television tries to protect the black and minimise the halo effect around bright objects. Unfortunately, this comes at the cost of details – some of the intricate details simply disappear, and the scene loses its nature.

The best factory mode in terms of colour reproduction was "Filmmaker". This was the one we used during our tests. Let's check how its characteristics looked before the calibration process. Looking closely at the white balance first, we can notice a significant dominance of red and green. As a result, the image had a warm yellowish hue. Such characteristics are typically observed in "Cinema", "Filmmaker" or similarly named modes. The effect of this colour balance was clearly visible in both SDR and HDR content, which after switching from "Standard" mode appeared distinctly yellow. Now, let's move on to two graphs that are responsible for the brightness characteristics and consequently the contrast of the image. The first one (Gamma), representing materials with a standard colour palette, performed decently. For most of the time, midtones and bright whites were reproduced very accurately; however, it noticeably lost the darkest details, which merged into a black blob. Conversely, HDR materials, represented by the EOTF curve graph, exhibited a significant drop in contrast due to a strong boost in brightness. The colours themselves also posed a problem, as can be seen on the "ColorChecker" graph, since they were noticeably under-saturated.

For colour tests, we once again reached for the Filmmaker mode – a new feature in TCL televisions for 2025. And although the direction itself is a step in the right direction, the execution leaves much to be desired. The white balance in SDR content turned out to be too warm – there was an excess of red. Conversely, 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 – managing brightness. Regardless of whether we were watching SDR or HDR content, the image had a tendency to blow out the entire scene, giving it an unnatural, almost grotesque character. Therefore, it is hard to call this a 'director’s mode' – because the director surely has never seen such an image.

The manufacturer has implemented extensive support for the calibration process in its LG televisions for many years. We therefore used 2- and 20-point greyscale adjustments, as well as an advanced CMS (Colour Management System), and got to work. As you can see, thanks to the procedure carried out, each parameter has significantly improved. The use of tools allowed for the achievement of extremely beneficial effects, which include: studio colour reproduction, recovery of details in dark areas of the image, appropriate brightness characteristics, and suitable colour saturation. This brings us as close as possible to the reference image, which is what the film director saw on the preview monitor. It is worth noting that the LG G4 televisions alone allow for even deeper intervention in image quality thanks to the ability to calibrate with 3D LUTs. However, this is a solution recommended only for post-production or graphic studios.

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 with 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 managing brightness was also brought under control in SDR content, and the effect was more than satisfactory. Unfortunately, when we switched on the HDR material, the situation quickly became complicated. No matter how we set the local dimming, the television had a tendency to do what it pleased with the image – either overexposing the whole picture or dimming the darkest parts too much. Just like we saw in the scene from the film Billy Lynn. Colour-wise, the improvement after calibration makes a great impression, but managing brightness in HDR remains the Achilles' heel of the C9K and constitutes a technological limitation.

The tested television did not perform particularly well with materials rich in tonal transitions, as a result of which we could observe a strong posterisation effect. However, there is a partial remedy for this issue. The manufacturer has equipped the LG G4 with a smoothing system called "Gentle Gradation," which we can apply at three levels: Low, Medium, and High. Each of these options guarantees quite a high effectiveness of smoothing on light colours, although it is low on darker ones. We recommend primarily using the first one, as the other two interfere with the director's intentions by removing film grain.

When watching lower-quality materials, the efficiency of the television during upscaling is extremely important. The image from the tested television is sharp and clear. However, one should pay attention to the jagged edges of fine details and minor issues around characters, such as the creation of halo effects, which occurs due to the sharpening imposed by LG G4 even when the lowest value on the slider, that is 0, is set. It is worth noting that this represents a certain change compared to the LG G3, which did not impose such strong image sharpening, even when the appropriate slider was set to position 0.

The digital image processing in TCL C9K is rather mediocre. The tone transition smoothing feature is supposedly present, but activating it hardly makes any difference – colour banding is still visible, and it can inadvertently highlight elements we would prefer to hide, such as textures of objects. Fortunately, it does not remove film grain, but that's scant consolation considering the effects are still poor. Thus, it's hard to recommend using this option.

On the other hand, image scaling performs significantly better. Lower quality materials look quite decent – characters and backgrounds are represented clearly, although of course, with sources like 576p, the limitations of the physics cannot be disguised. Sometimes, there's characteristic aliasing of objects, but that's due to the source itself, not the algorithm. A plus for the fact that there are no overscan issues – the image is neither artificially cropped nor enlarged.

The maximum refresh rate that we can set on the LG G4 is 144 Hz. Naturally, this is only possible when the LG G4 is connected to a very powerful PC. Otherwise, we will operate at a maximum refresh rate of 120 Hz, which is recommended if we primarily want to watch sports or content with high motion dynamics. For those requiring high image fluidity, the manufacturer has implemented a multi-level motion smoother called "TrueMotion". This has been divided into two separate sliders that adjust the sharpness of moving images (De-Blur) and judder (De-Judder). Both sliders can be set in the range from 0 to 10, with each level affecting the degree of smoothness, allowing everyone to find their golden mean.

The LG OLED G4 panel features an average response time of 0.78 ms (as directly derived from our measurements), enabling an incredibly clear image, unattainable by LCD televisions, which can have response times of several milliseconds. This is perfectly illustrated by the images from the "UFO Test", which show no trailing blur behind the object. Moreover, the LG OLED G4 test revealed that the television offers the ability to precisely adjust the motion smoothing function, allowing users to select the ideal level of image interpolation. We particularly appreciated this during fast-paced actions in video games, where the LG G4 performed exceptionally well, minimising any blurring. Thanks to OLED technology, this model eliminates so-called ghosting, ensuring that the image remains sharp even in the most dynamic sporting or cinematic scenes.

Similar to the C8K, the C9K is also a really fast television – both figuratively and literally. On board, we have 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 picture looks very smooth and clear. Additionally, in films, we get an extra motion smoothing feature called Motion Clarity, which allows you to adjust the smoothness to your own preferences – from the cinematic "stuttering" of frames to nearly theatrical smoothness.

The LG G4 television supports all the features that make up the HDMI 2.1 standard. During testing, each of them activated without the slightest problem, which allows us to consider the television as designed for gaming. Their functionality will surely be appreciated by both console users and those connecting the LG G4 to a computer. It is also worth mentioning the correct implementation of the HGIG (HDR Gaming Interest Group) mode, which ensures that games mastered to brightness levels exceeding the maximum luminance of the LG G4 will correctly map tones, and the game's visuals will remain true to the original.

A nice touch is the existence of a special GameBar, which we can call up at any moment to check game parameters, but most importantly, to change them quickly. More importantly, enabling VRR technology does not degrade contrast, which is very common in televisions that feature local dimming or Mini LED backlighting. Of course, this is thanks to the OLED panel itself, characterised by pixel self-emission. As a matter of editorial obligation, we will only mention a slight grey flicker, which is somewhat normal after enabling VRR.

In summary, the LG G4, like practically all OLED televisions, is an ideal product for all kinds of games and online competitions. With fully-fledged HDMI 2.1 connections with a full bandwidth of 48 Gbit, features such as VRR, ALLM, G-Sync, FreeSync, or gaming in HDR Dolby Vision will bring much joy.

For gaming, the TCL C9K is a complete tool. Here we have two (out of four) HDMI 2.1 ports with full bandwidth of 48 Gbps, 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, which allows you to quickly check the most important parameters and adjust settings without rummaging through the menu. Also worth noting is TCL's policy – the television does not shy away from 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 a wide range of freedom.