LG OLED G4 vs Samsung QN990F

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.

The Samsung QN990F belongs to the bright televisions and this is immediately evident in the tests. In measurements, it achieved around 1300 nits, which in practice allows you to enjoy movies as their creators intended. Bright scenes have the right impact, lights shine, and the feeling is truly cinematic. In standard test patterns, sequences number 1, 3, and 5 performed the best – there the brightness remained around 800-1000 nits, and the image looked very natural. In more challenging segments, it could drop to about 600 nits, but still the level remained sufficient for details to be well visible. However, it should be added that with such highly contrasted shots, the halo effect returns – the same one we mentioned regarding the blacks. Bright elements can leave a glow on dark backgrounds, and this is immediately noticeable. Since we are dealing with a QLED, the color palette is expanded and the colors look impressive. The problem is that with such a flagship model, we expected better numbers. 91% coverage of DCI-P3 and about 67% BT.2020 are results that can be considered solid, but not outstanding. This results in a vibrant and attractive picture; however, competition in this and lower price segments can show even more.

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.

We tested the QN990F in Filmmaker mode, which is the best available right out of the box. Right from the start, we noticed several significant errors. The biggest issue was with white balance. Due to too little blue and also incorrect proportions between red and blue, the image – especially in scenes with a lot of white – appeared too yellow and at times even orange. On the Color Checker palette, these errors didn't look dramatic as they hovered around a value of 4, but in everyday viewing, especially with strong whites, they were most noticeable. We also noticed issues with brightness management – the television had difficulty maintaining details in the smallest parts of the image, mainly due to the way it controls the backlight zones. Fortunately, Samsung offers a lot of room for adjustment when it comes to setting corrections. We know that with proper calibration, you can definitely get a lot more out of this screen.

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 performing calibration, we managed to bring the white balance into order and eliminate the previous deficiencies in blue tones. As a result, the image no longer appeared as if it had a slightly yellowish filter – whites are cleaner, and the overall presentation looks much more natural. We also managed to some extent to tame the brightness characteristic in HDR content. The television now handles maintaining details in blacks significantly better and does not lose them as much as before. However, when we look at the EOTF curve and how the QN990F reproduces brightness in films, it is evident that it still tends to emphasize details in dark scenes more strongly. This is a characteristic feature of Mini-LED technology, and more specifically, how it is managed by the QN990F, which is practically impossible to completely eliminate. Nevertheless, after calibration, the image looks much more natural, primarily due to the correct exposure of white light. The final effect is definitely more pleasant to receive and closer to what we expect from a flagship television.

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.

The QN990F deserves the highest praise for its upscaling. The processor responsible for "pulling up" classic TV to 8K resolution performs quite well. While watching content in a 576p signal, we had no illusions that we would suddenly see a marketing-style miracle where the image magically transforms into crystal-clear 8K. Nevertheless, the final effect was surprisingly good; the image looked clean and clear. It's just unfortunate that the TV, like most Samsung models, has an overscan issue, which slightly cuts off the edges of the screen on the left side.

Regarding image processing, Samsung provides a feature called "noise reduction," which in theory should improve tonal transitions in older materials, where they are usually more noticeable. Unfortunately, we felt quite disappointed here. The feature works poorly – it struggles with unwanted bands and can even introduce its own artifacts. On the plus side, the TV does not eliminate film grain when using this feature, but in practice, that's little consolation since the noise reduction itself proves to be practically useless.

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.

The QN990F can easily be called one of the fastest televisions in the world. In 4K mode, it can display images at a frequency of up to 240 Hz, which until now has been more associated with gaming monitors than with televisions in the living room. However, in everyday viewing, what matters more is how it handles 8K signals at 120 Hz – and it performs very well here too. Motion remains smooth, and the television manages without a hitch even with the most demanding content. Additionally, there is a motion smoother, called "Picture Clarity." With it, you can adjust the image to your own preferences – leave a slight cinematic stutter or switch to maximum smoothness, which works great, for instance, in sports broadcasts.

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.

It must be said directly – the QN990F is one of those TVs that screams it was designed with gamers in mind. Samsung has been developing its gaming solutions for years, but here we have a true package. Sure, the lack of Dolby Vision support in games is a downside that will always come up in discussions. However, apart from that, the list of features is truly impressive. To start, we have Game Bar – a handy menu that allows you to quickly check and change game-related settings. You can see, for example, VRR is turned on, the frame rate, or the aspect ratio settings. It's like a small "dashboard," allowing you not to dig deep into the menu to make adjustments. Speaking of VRR: yes, variable refresh rate is present here and works flawlessly. Additionally, there's ALLM, which automatically switches the TV to game mode as soon as the console is turned on. These may seem like small details, but together they make using the QN990F simply convenient and hassle-free.

However, the number of ports makes the biggest impression. Four wireless HDMI 2.1 ports are already great news because you don't have to choose whether to connect the console, the receiver, or maybe even the PC. There's plenty of room here for everything. And if we add an additional micro HDMI (which we recommend connecting directly to consoles), hidden in the housing, we practically have five inputs in full 2.1 standard. Add to that support for high refresh rates – 120 Hz in 8K or even 240 Hz in 4K – and we get a TV that not only keeps up with the new consoles but also feels ready for consoles that are yet to come.