LG 38UC99 38-inch Curved Ultra-Wide FreeSync Monitor Review

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Grayscale, Gamma & Color

Grayscale Tracking

Our grayscale and gamma tests are described in detail here.

None of the 38UC99’s image modes stray too far from D65, but the closest one is Custom, which happens to be the default setting. If you don’t plan to calibrate, we suggest using that preset for both gaming and productivity. It runs a tiny bit green at 90% and 100%, but you’d be hard-pressed to see the issue.

FPS Game 1 also measures pretty close to the mark and doesn’t look that different from Custom. It just makes a slight tweak to gamma and color. It also locks out all adjustments except brightness so you can’t dial it in to taste. Only Custom offers that flexibility.

After working the RGB sliders a bit, we achieved near perfect tracking. The 38UC99 comes with a factory-certified calibration but only for grayscale and gamma. While it matches the enclosed data sheet closely, there is just a bit more quality left for tweakers like us to find. This is seriously excellent performance.


As impressive as the 38UC99’s before-and-after results are, they aren’t enough to take the win in this group of premium screens. But LG can still be proud that its 34UC98 wears the crown here. Seriously though, there is nothing to complain about in either chart except for AOC’s out-of-box number. And that is easily repaired with a few changes to the OSD. These monitors may be expensive, but they deliver performance commensurate with their price-tags.

Gamma Response

There is very little to be said about the 38UC99’s gamma performance other than that it’s awesome. Even the FPS Game 1 mode barely changes the tracking. There, a little more emphasis is placed on highlight and shadow detail, but it’s barely visible. Calibration doesn’t affect the result at all either. It can’t get much better than this.


A .04 range of values is about as tight as it gets for any display. In fact, only one monitor has scored better in this test with a .03 result — that would be BenQ’s PV3200PT professional video editing display. In the LG monitor's case, it helps boost perceived contrast a little and adds some additional depth to the image. Though it only achieved an average result in our contrast tests, its super accurate gamma helped make it look much better than the numbers suggest. With an average value of 2.17, the top three monitors (including our review subject) are only 1.36% off the standard.

Color Gamut & Luminance

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

LG didn’t include color gamut measurements in its calibration data sheet, but it might as well have. The out-of-box charts are excellent. Aside from slight over-saturation in the two highest red points, every measurement is on target. Luminance levels are ideally balanced as well. Blue has been pumped up slightly to compensate for the tiniest under-saturation. And red does the opposite, dropping its brightness just a little to make up for being over-saturated. Resulting average error levels are extremely low. Out of the box, the average is 1.34dE. FPS Game 1 mode returns 1.68dE and the calibrated result is .90dE. The 38UC99 offers all the quality and accuracy of the best professional monitors we’ve tested.


With our minor adjustments in place, the 38UC99 takes the color accuracy crown, narrowly edging its 34UC98 stablemate. There’s no reason this monitor can’t be used as a proofing tool provided you don't need the wider Adobe RGB color gamut. To that end, it covers sRGB with a little bonus red taking total volume up over 104%. This likely represents the best gamut performance possible from an IPS panel with a white LED backlight.

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. Christian began his obsession with tech when he built his first PC in 1991, a 286 running DOS 3.0 at a blazing 12MHz. In 2006, he undertook training from the Imaging Science Foundation in video calibration and testing and thus started a passion for precise imaging that persists to this day. He is also a professional musician with a degree from the New England Conservatory as a classical bassoonist which he used to good effect as a performer with the West Point Army Band from 1987 to 2013. He enjoys watching movies and listening to high-end audio in his custom-built home theater and can be seen riding trails near his home on a race-ready ICE VTX recumbent trike. Christian enjoys the endless summer in Florida where he lives with his wife and Chihuahua and plays with orchestras around the state.

  • Warsaw
    Just have to sell my kidney now to get one....
  • Geekwad
    Looks like a great professional monitor, but not gaming (though I'm really happy to see the FreeSync adder anyway). If the range was ~35hz to 75hz, it'd be very different.

    Still, this looks to be a really great product for content creators.
  • falchard
    For the price you can get 3 of LGs top range 27" 4k ips monitors which would probably be more effective. Still it's a nice halo product for selling panels.
  • ap3x
    it runs at 75hz by the way and it supports freesync. I have the 34UM95 which was the first model they release and it is fantastic for productivity and great for strategy games but not as much for FPS's. This monitor would be great all around and much better than having 3 separate monitors at 4k since that would basically difficult to run at any resolution that would take advantage of 4k x3. The immersion would also not be much better in that configuration because you already have to move your head to look at things with an ulrawide. 4k peripheral monitors is a waste anyway even if you could run it.
  • Kowmander
    The price of my Seiki 40" 4k makes me happier than the extra features I'm missing. But I do see the value of a curved screen at that width + desktop viewing distance.
  • ubercake
    23Hz range for freesync?

    Just plopping "freesync" in there for the sake of being able to say "freesync" is weak.

    That said, I think LG IPS panels are the best.
  • falchard
    I am more surprised at manufacturers refusing to add freesync verse those that tack it on. A monitor with displayPort and neither gsync or freesync is baffling
  • Niva
    This is one amazing monitor. For the first time I'm seeing something which makes me consider my 30" Dell long in the tooth.
  • falchard
    You could also wait just a little more. LG tvs are starting to get cheaper Oled and HDR. We could see these coming to monitors in the next 2 years.
  • zon
    I would like to see this monitor go up against an Samsung CF791 when it gets released.
    Still don't get why TV's are HDR and not PC monitors yet. OLED is understand able with the issue with the blue sub pixel and the burn-in. But heard they fixed the blue sub pixel to an extent.