LG UltraGear 27GX790A-B / MSI MPG 491CQP QD-OLED

LG UltraGear 27GX790A-B: 27-inch class (26.5-inch) QHD 480 Hz OLED

MSI MPG 491CQP QD-OLED: MPG 491CQP QD-OLED, 49-inch 32:9 curved monitor. The Samsung Odyssey OLED G9 of the same size and MSI’s other 49-inch models are separate.

SpecificationLG UltraGear 27GX790A-BMSI MPG 491CQP QD-OLED
Release year20252024
Model27GX790A-B (US version 27GX790A-B.AUS)

LG’s US spec sheet carries a 2024 copyright; LG Brazil lists the model as a 2025 product.

LG		—
Panel26.5-inch (27-inch class) OLED, 16:9

The actual viewable diagonal is 26.5 inches.

LG		49-inch QD-OLED; 5120 × 1440 (DQHD), 32:9; 1800R curve

The 32:9 ratio gives a workspace equivalent to two 27-inch 1440p monitors side by side. The 1800R curve keeps the edges closer to the eyes.

MSI
Resolution and pixel pitch2560 × 1440 (QHD); 0.2292 mm pixel pitch

QHD at 27 inches means lower pixel density than 4K; small text looks less crisp but high frame rates are easier to reach on the GPU.

LG		—
Refresh rate480 Hz

480 Hz means up to 480 frames per second; seeing that benefit requires the game and GPU to deliver close to 480 fps.

LG		—
Response time0.03 ms (GtG)

Grey-to-grey pixel transition time; it is not input lag.

LG		—
BrightnessTypical 275 cd/m² (min 250); HDR peak at 1.5% APL typical 1,300 cd/m² (min 1,040)

1,300 nits applies only to small highlights covering 1.5% of the screen; on a full white screen OLED automatic brightness limiting kicks in.

LG		—
Contrast1,500,000:1 (typical)

OLED pixels can switch fully off, so black level is near zero; LG’s page notes the figure is measured at 25% APL.

LG		—
ColourDCI-P3 98.5% (CIE 1976); 10-bit (1.07 billion colours)

The sheet lists a paper calibration report in the box.

LG		99% DCI-P3, 146% sRGB, 98% Adobe RGB; 10-bit (1.07 billion colours) MSI
HDRHDR10; VESA DisplayHDR True Black 400

True Black is the VESA HDR tier for very low black-level displays such as OLED.

LG		—
Variable refreshVESA AdaptiveSync; NVIDIA G-SYNC Compatible; AMD FreeSync Premium Pro

Variable refresh matches the panel to the GPU frame rate to reduce tearing and stutter. LG’s page also lists VESA ClearMR 21000 certification.

LG		—
Screen surfaceAnti-glare, low-reflection front polariser LG—
Inputs2× HDMI (HDMI 2.1 FRL compliant); 1× DisplayPort 2.1

FRL is the high-bandwidth transfer mode of HDMI 2.1. There is no USB-C video input.

LG		—
USB and audioUSB 3.0: 1 upstream, 2 downstream; 4-pole headphone out (sound + mic); DTS Headphone:X

No built-in speakers are listed.

LG		—
StandTilt -5°/15°; swivel -30°/30°; height 110 mm; clockwise pivot; VESA 100 × 100

It has a tool-free 1Click stand mount and hexagonal RGB lighting on the back.

LG		—
PowerExternal adapter, 100–240 V; under 0.5 W in sleep, under 0.3 W off

The sheet does not list typical power consumption.

LG		—
Burn-in careOLED Care

LG says the feature helps prevent burn-in from static high-contrast images left on screen for long periods but may not prevent all image retention.

LG		—
Size and weightWith stand 23.8 × 22.8 × 9.8 in (raised), 20.5 lb; without stand 23.8 × 13.8 × 1.8 in, 11.2 lb

About 9.3 kg with stand, about 5.1 kg without.

LG		With stand 1195 × 328 × 410 mm; without stand 1195 × 190 × 372 mm; net 10.3 kg MSI
In the boxPower cord, DisplayPort 2.1 cable, HDMI 2.1 cable, USB A-to-B cable, paper calibration report LG—
Refresh and response—144 Hz (adaptive range 48–144 Hz); 0.03 ms (GtG)

Adaptive sync prevents tearing while the frame rate stays between 48 and 144. Reaching 144 fps at full resolution needs a very powerful graphics card.

MSI
Brightness and contrast—Typical SDR 250 nits; 1,500,000:1; DisplayHDR True Black 400

True Black 400 is the OLED-class certification for very low black level and 400-nit HDR brightness.

MSI
Adaptive sync—AMD FreeSync Premium Pro

The Premium Pro tier includes low frame rate compensation and low-latency tone mapping in HDR.

MSI
Connections—1 × DisplayPort 1.4a; 2 × HDMI 2.1; 1 × USB-C (DP Alt Mode, 90 W PD); 2 × USB 2.0 Type-A; 1 × USB 2.0 Type-B; headphone out

USB-C takes video from a laptop over one cable and charges it at up to 90 W. The USB ports run at USB 2.0 speed; there are no built-in speakers.

MSI
Multi-view—PiP / PbP

PbP splits the 49-inch screen side by side between two sources to show two computers at once; PiP shows one source in a small window over the other.

MSI
Surface—Anti-reflection coating MSI
Stand and mounting—Tilt –5° to 20°; swivel –30° to 30°; height 0–100 mm; VESA 100 × 100 MSI
Warranty—3 years, including panel burn-in

Static images left on an OLED panel for long periods can leave permanent marks; MSI covers this risk under warranty.

MSI