ASUS ROG Strix OLED XG27UCDMG / LG UltraGear 27GX790A-B

ASUS ROG Strix OLED XG27UCDMG: XG27UCDMG · 26.5-inch 4K 240 Hz QD-OLED

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

SpecificationASUS ROG Strix OLED XG27UCDMGLG UltraGear 27GX790A-B
Release year20252025
Panel26.5-inch (27-inch class) QD-OLED, 16:9, anti-reflection surface

QD-OLED pairs self-emitting pixels with a quantum-dot colour layer; each pixel switches off individually, so blacks are fully dark.

ASUS		26.5-inch (27-inch class) OLED, 16:9

The actual viewable diagonal is 26.5 inches.

LG
Resolution and refresh3840 × 2160, 240 Hz

The 4K 240 Hz signal travels over DisplayPort 1.4 with DSC compression, or over HDMI 2.1 depending on graphics-card support.

ASUS		—
Response time0.03 ms (GtG)

This is the grey-to-grey pixel transition time, not total input lag.

ASUS		0.03 ms (GtG)

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

LG
Brightness1000 cd/m² HDR peak

ASUS notes peak brightness may vary with colour pre-calibration; the peak is reached on a small screen area.

ASUS		Typical 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) ASUS1,500,000:1 (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
Colour99% DCI-P3, 145% sRGB; ΔE < 2; 10-bit

Factory calibration (ΔE < 2) means colours are set close enough to target that differences are hard to see.

ASUS		DCI-P3 98.5% (CIE 1976); 10-bit (1.07 billion colours)

The sheet lists a paper calibration report in the box.

LG
HDRHDR10; VESA DisplayHDR 400 True Black ASUSHDR10; VESA DisplayHDR True Black 400

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

LG
Inputs1 × DisplayPort 1.4 (DSC); 2 × HDMI 2.1 (FRL); 1 × USB-C (DP Alt Mode, 90 W power)

The USB-C input takes video from a laptop and charges it at up to 90 W over one cable. HDMI 2.1 suits consoles at 4K 120 Hz.

ASUS		2× 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 hub and audio3 × USB 3.2 Gen 1 Type-A; headphone jack ASUS—
Variable refreshFreeSync Premium Pro, G-SYNC Compatible; VESA AdaptiveSync Display 240 Hz

Variable refresh matches the screen's rate to the graphics card's frame rate, reducing tearing and stutter.

ASUS		VESA 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
FeaturesASUS OLED Care, KVM switch, Extreme Low Motion Blur, Neo Proximity Sensor, flicker-free

KVM shares a keyboard and mouse connected to the monitor between two computers. The proximity sensor dims the screen when the user leaves to reduce OLED wear.

ASUS		—
Power consumption< 80 W; < 0.5 W in power saving; < 0.3 W off; 100–240 V ASUS—
StandTilt +20°/−5°, swivel ±45°, pivot ±90°, 0–120 mm height; VESA 100 × 100; 1/4-inch tripod socket

The tripod socket lets a camera or light be mounted on the stand.

ASUS		Tilt -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
Dimensions and weightWith stand 61.30 × 50.94 × 16.87 cm, 7.44 kg; without stand 61.03 × 36.92 × 6.65 cm, 5.0 kg ASUS—
Warranty3 years (including panel burn-in)

Warranty terms may vary by country.

ASUS		—
In the boxDisplayPort, Ultra High Speed HDMI, USB 3.2 and USB-C cables; power cord; VESA mount kit; microfibre cloth ASUSPower cord, DisplayPort 2.1 cable, HDMI 2.1 cable, USB A-to-B cable, paper calibration report LG
Model—27GX790A-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
Resolution and pixel pitch—2560 × 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 rate—480 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
Screen surface—Anti-glare, low-reflection front polariser LG
USB and audio—USB 3.0: 1 upstream, 2 downstream; 4-pole headphone out (sound + mic); DTS Headphone:X

No built-in speakers are listed.

LG
Power—External 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 care—OLED 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 weight—With 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