Skip to main content

LG 27GN950-B 4K 144Hz Monitor Review: One Fast Pixel Mover

One of the fastest 4K monitors we've ever tested

LG 27GN950-B
Editor's Choice
(Image: © LG)

Grayscale and Gamma Tracking

We describe our grayscale and gamma tests in detail here.

Gamer 1 is the LG 27GN950-B’s default picture mode and it is accurate enough to make calibration optional. The only restriction is that you’re locked into the P3 color gamut. Grayscale is a tad cool though you’ll be hard-pressed to spot a problem. Gamma tracks close to 2.2 except for a little dip at 70-90%. This means light levels rise too quickly which might make some highlight details less crisp.

Calibration required a bit of trial and error as we tried all four gamma presets. We wound up changing it from Mode 1 to Mode 4, then clicking the red slider up one. Grayscale tracking is now essentially perfect with no visible errors. Gamma is a little darker at the 50-90% end of the scale but this makes color more vibrant and gives the image greater depth. It looks great at 200 nits and if you want more visibility, just increase the brightness slider.

The sRGB mode has a few issues that limit its usefulness. Grayscale tracking is only fair with a slight red tint across the board. Gamma at 80 and 90% is too dark which muddles highlight detail. And as you’ll see below, the color gamut is still well past the perimeter of sRGB. If you want accurate sRGB, the 27GN950-B can only deliver it with LG’s True Color Pro Software.


The 27GN950-B’s Delta E (dE) values are strong, placing it a little above average when compared to our full monitor review database. The Samsung and Acer screens are the over-achievers here. 2.03dE is very good and most users will be satisfied with the panel’s default settings in the Gamer 1 picture mode. Calibration brings a visible gain though and we recommend it. 0.87dE is pro monitor territory.

Gamma tracks tightly with a small 0.17 range of values. Though we couldn’t get all brightness levels on the 2.2 line, it’s close to the mark. A 3.18% deviation is a tad below average, but the error is to the dark side which is preferable. Color is nicely saturated, detail is sharp, and contrast is deep.

Color Gamut Accuracy

For details on our color gamut testing and volume calculations, click here.

The LG 27GN950-B fared well in our color gamut tests. The P3 gamut error was just 1.68dE by default. The screen has a greater volume than most and that bodes well for image quality. Saturation is excellent with vivid and natural hues throughout. Calibration increases that saturation slightly, but the result can be seen with the naked eye. Errors are practically non-existent.

The sRGB mode doesn’t look as good in our tests. Though it provides plenty of bold color, it far exceeds the boundaries of the gamut spec. If you want true sRGB color, this mode won’t deliver it.


With a 1.27dE average color gamut error, the 27GN950-B beats most of its competition in color accuracy. Even without calibration it looks great. This is excellent performance.

In the volume calculation, the LG 27GN950-B also excels. Only a handful of monitors we’ve tested have more than 95% coverage. You can see how oversaturated the sRGB mode is. Though it reduces the gamut a little, it still covers over 133%. The only way to rein it in is with LG’s True Color Pro software which can apply an internal LUT and save it to one of two calibration picture modes.

Christian Eberle
Contributing Editor

Christian Eberle is a Contributing Editor for Tom's Hardware US. He's a veteran reviewer of A/V equipment, specializing in monitors.

  • CXB
    The most recent firmware to the LG 27GN950-B pushes the display rate to 160Hz at 4k (the firmware takes a nervous 30+ minutes to load)
    A very nice monitor, well-suited to DisplayPort, DSC and the new graphics cards coming out (I was lucky to bag an RTX3070)
  • Wanderingm00se
    Honestly, if this had an HDMI 2.1 it would have been an instant buy for me running this well. Maybe a refresh next year will have it. Got a series X as video card prices in Canada are insane right now if available and consoles are almost readily available and are cheaper than US pricing after conversion.
  • tomy_12
    I heard with this monitor cannot cancel the option that the monitor will go to deep sleep, is kind of big let down when the monitor fall a sleep and can't wake up. I don't want my monitor to fall a sleep, I can make the pc set to sleep mode alone. would be nice if you can mention it in the review.
  • CXB
    Well, you may have heard that, but I've just left my PC and my LG 27GN950 alone for 4 hours, and as soon as I hit my space bar on the keyboard, everything just woke up where it had left off.

    What I do find is that sometimes, with a second monitor, the GPU gets in a twist. But that's not a problem related to this monitor.