LG OLED G4 vs TCL C9K

The LG G4 excels in delivering an incredibly vivid HDR experience, positioning it as one of the best models in its class. Equipped with second-generation Micro Lens Array (MLA) technology, it achieves a remarkable peak brightness of 1474 nits in real-world scenes. While it may not match Mini LED-backlit LCD TVs in full-screen white scenes, the overall performance is outstanding. The fine details in HDR content shine brightly, a distinct advantage of OLED technology over non-OLED displays. With this impressive brightness and wide DCI-P3 colour gamut coverage, HDR content is brought to life with unmatched engagement and immersion.

As we mentioned with black 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 is capable of squeezing out… 4000 nits of brightness! It sounds astronomical, but – and here, unfortunately, the pattern repeats – the numbers say one thing, and practice says another. In real movie scenes, the situation looks different. At best, when the light effects occupy a large part of the image and the local dimming algorithm does not have to think too hard about what to do with thousands of zones – the effect is really good. At that point, the C9K can reach around 1500 nits, which provides a pleasant, intense flash and can indeed make a positive impression.

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

Before calibration, the "Filmmaker" mode on the TV had a noticeable red and green colour dominance, resulting in a warm-yellow hue across both SDR and HDR content. This warm tone, typical of modes like "Cinema" and "Filmmaker," led to a yellowish cast that was evident when switching from the "Standard" mode.

Looking at the brightness characteristics, the Gamma chart showed decent performance for mid-tones and bright whites, but it struggled with the darkest details, which tended to merge into a black blob. HDR content, as represented by the EOTF curve chart, displayed a drop in contrast due to excessive brightness, which overshadowed fine details and negatively affected the overall image quality. Additionally, the "ColourChecker" chart revealed that colours were under-saturated, contributing to a less accurate and vibrant visual experience.

This provided a good foundation to build on, but calibration was needed to bring out the full potential of the "Filmmaker" mode and address these issues.

For color tests, as always, we reached for the Filmmaker mode – a new feature in TCL TVs for 2025. And while 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. On the other hand, in HDR, it went in the opposite direction: the image became excessively blue. The Colour Checker test revealed quite a few color errors 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 blow out the entire scene, giving it an unnatural, even grotesque character. It's hard to call this a "director-created" mode – because the director has certainly never seen such an image.

The manufacturer has been offering extensive support for the calibration process in its LG televisions for many years. Therefore, we used 2- and 20-point grayscale adjustments along with an advanced CMS (Colour Management System) to optimise the display. As shown, the calibration procedure greatly improved each parameter. The results included studio-quality colour reproduction, enhanced detail in dark areas, corrected brightness characteristics, and accurate colour saturation. This led to a near-perfect match with the reference image—the one the film director saw on the preview monitor. It’s also worth mentioning that LG G4 televisions are unique in offering even deeper image adjustments through 3D LUT matrices, a feature primarily suited for post-production or graphics studios.

After calibration, we finally managed to tame the white balance – and it immediately translated into a more natural image. Colors finally started to look the way they should, and the overall presentation was incomparably better than in the factory settings. In other words – it’s worth taking a moment to improve this, as the gain is truly significant. The gamma responsible for managing brightness was also brought into order in SDR content, and the effect was more than satisfying. 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 dimmed the darkest parts too much. Exactly as we saw in the scene from the movie Billy Lynn. So, the color improvement after calibration makes a great impression, but brightness management in HDR remains the Achilles' heel of C9K and presents a certain technological limitation.

The LG G4 does not perform well with materials rich in tonal transitions, leading to a pronounced posterization effect. However, the manufacturer has included a smoothing system called "Gentle Gradation," with three levels: Low, Medium, and High. These settings are effective at smoothing bright colours, though less so for darker tones. It is recommended to use the Low setting, as the higher levels can distort the director's intentions by removing film grain.

When it comes to upscaling lower-quality material, the television's performance is quite good, delivering a sharp and clear image. However, attention should be paid to the jagged edges of fine details and the occasional halo effect around figures. This occurs due to the sharpening imposed by the LG G4, even when the lowest setting is selected (0). This is a noticeable change from the LG G3, which did not apply such strong sharpening, even at setting 0.

Digital image processing in TCL C9K is quite mediocre. The tonal smoothing feature seems to be present, but turning it on practically changes nothing – color bands are still visible, and it can unintentionally highlight elements we would prefer to hide, such as textures of objects. Fortunately, it doesn’t remove film grain, but that’s small comfort since the effects are still poor. Therefore, it's hard to recommend using this option.

On the other hand, image scaling performs much better. Lower quality materials look quite decent – characters and backgrounds are presented clearly, although, of course, with sources at 576p, physics cannot be fooled. Sometimes, characteristic aliasing on objects appears, but that’s the fault of the source itself, not the algorithm. A plus for not having issues with overscan – the image is not artificially cropped or enlarged.

The LG G4 offers a maximum refresh rate of 144 Hz, achievable when connected to a powerful PC. For most users, however, the TV operates at a maximum of 120 Hz, ideal for watching sports or other content with fast motion. To improve image fluidity, the television includes the "TrueMotion" motion smoothing system, which features two separate sliders: De-Blur (for the sharpness of moving images) and De-Judder (for judder reduction). These sliders allow users to adjust the level of smoothing between 0 and 10, ensuring everyone can find the ideal setting.

With a response time of 0.78 ms, the LG G4 delivers exceptionally clear images, outperforming LCD televisions, which can have much slower response times. This results in no trailing blur behind moving objects, as shown in the "UFO Test." The TV also provides precise control over motion smoothing, which is especially beneficial during fast-paced video game sequences. Thanks to OLED technology, the G4 eliminates ghosting, ensuring a crisp and clear image even during the most dynamic sports or action scenes.

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

The LG G4 TV supports all the features encompassed by the HDMI 2.1 standard, making it a gaming powerhouse. During testing, every feature activated seamlessly, ensuring a smooth experience for both console gamers and PC users. Notably, the HGIG mode (HDR Gaming Interest Group) is implemented correctly, allowing games mastered to brightness levels higher than the TV’s maximum luminance to map tones accurately, preserving the game’s original visual integrity.

A notable highlight is the dedicated GameBar, which can be accessed at any time to quickly check or adjust game settings. More importantly, enabling VRR (Variable Refresh Rate) does not compromise contrast—a common issue in TVs with local dimming or Mini LED backlighting. This is thanks to the OLED panel’s self-emissive pixels, which maintain consistent contrast. However, a slight grey flicker may appear when VRR is enabled, though this is standard across OLEDs.

In summary, the LG G4, like most OLED TVs, is ideal for gaming and online competitions. Its HDMI 2.1 ports offer a full 48 Gbps bandwidth, supporting features such as VRR, ALLM (Auto Low Latency Mode), G-Sync, FreeSync, and HDR Dolby Vision gameplay, ensuring an exceptional gaming experience.

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 key technologies work: VRR (variable refresh rate) and ALLM (automatic low latency mode). Additionally, the manufacturer added a really intuitive Game Bar, which allows you to quickly preview the most important parameters and adjust settings without digging through the menu. Also, TCL's policy is a plus – the TV is not 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 wide freedom.