Monitors · 2026 · LG

LG UltraGear evo GX9 39GX950B-B

The 39GX950B-B is a curved 38.86-inch OLED gaming monitor with a 5120 × 2160 panel. It runs 5K2K at 165 Hz and can switch to 330 Hz at 2560 × 1080 with Dual-Mode. Its USB-C input carries video, data and up to 90 W of power; there is no built-in KVM.

39GX950B-B · 38.86-inch · 5K2K · black

LG UltraGear evo GX9 39GX950B-B — Front view of the black 39GX950B from the LG UK model page; the on-screen text is promotional artwork.
Front view of the black 39GX950B from the LG UK model page; the on-screen text is promotional artwork.

Specifications

SpecificationValue
Display38.86-inch OLED · 5120 × 2160 · 21:9
Curvature1500R
Pixel pitch0.1776 × 0.1776 mm
Refresh rate165 Hz (5120 × 2160)
Dual-Mode330 Hz at 2560 × 1080 in the 21:9 modes; 330 Hz at 1920 × 1080 in the 16:9 modes

The product page calls this mode QHD in one place and WFHD in another; the resolutions in the manual were used. Exit the game before changing the mode.

Pixel response0.03 ms GtG

Not total input lag.

Brightness335 nits typical; 300 nits minimum
Peak HDR brightness1500 nits

Peak figure LG states under internal test conditions; not sustained full-screen brightness.

HDR formatsHDR10; VESA DisplayHDR True Black 500; no Dolby Vision
Colour coverageDCI-P3 99.5% typical, 94% minimum (CIE1976); 1.07 billion colours
Contrast ratio1,850,000:1 typical; 1,480,000:1 minimum

Manufacturer figure.

SurfaceAnti-glare, low-reflection front polarizer
CalibrationFactory calibrated; hardware-calibration ready (LG Calibration Studio)
Variable refreshG-SYNC Compatible; FreeSync Premium Pro
DisplayPort1 × DisplayPort 2.1; UHBR20

The graphics card and cable must support this rate.

HDMI2 × HDMI 2.1

The menu has 2.1(PC) and 2.1(AV) compatibility options. The product page connectivity table omits the HDMI count; the two inputs in the manual were used.

USB-C input1 × USB-C; video, data and up to 90 W power

The manual lists DP Alternate Mode and Power Delivery. The port does not power the monitor; the adapter is required.

USB hubUSB-C upstream; 2 × downstream USB 3.2 Gen 2

The manual says the downstream ports run at USB 2.0 over a USB-C to USB-C cable and USB 3.0 over a USB-C to USB-A cable.

Multiple sources2 × PBP and PIP; no built-in KVM
Audio2 × 7 W speakers; 4-pole headphone output; AI Sound
StandTilt −8° / +15°; ±30° swivel; 110 mm height adjustment

The manual does not describe pivot rotation.

Wall mount100 × 100 mm; 4 × M4 × L10 screws; optional LSW149 plate
Dimensions921.4 × 605.4 × 322.8 mm with stand (up); 921.4 × 495.4 × 322.8 mm (down); 921.4 × 405.0 × 118.7 mm without stand

Width × height × depth.

Weight10.7 kg with stand; 6.8 kg without
PowerExternal adapter; 40.3 W on-mode in SDR, 45.9 W in HDR

On-mode power demand from the product information sheet.

OLED careScreen saver; Image Cleaning of about 10 minutes

The manual states that prolonged use can cause permanent brightness reduction and image retention.

LightingUnity Hexagon Lighting 2.0 on the back
Warranty2 years; OLED panel included

From the manufacturer

LG presents the model as the world’s first 39-inch 5K2K OLED gaming monitor and highlights 1500-nit peak brightness, AI upscaling and Dual-Mode. LG UK

Strengths and limitations

  • TFTCentral measures about 335 nits in the uniform mode with little ABL. Brighter modes add more ABL. In HDR it measures about 1430 nits at the high peak setting and about 800 nits at the low setting.

    One review sample; Gamer 1 mode. Firmware version not stated.

    TFTCentral: LG UltraGear Evo 39GX950B review

  • The same review says the current subpixel layout largely resolves text fringing for most users. It suggests 125% scaling for a comfortable text size.

    One review sample; desktop text observation.

    TFTCentral: LG UltraGear Evo 39GX950B review

  • The AI upscaling works only when the screen detects a non-native signal, does not work in Dual-Mode and helps most with 1080p 60 Hz sources. The reviewer finds its use cases very limited.

    One review sample; on many PC setups the GPU already scales the image to 5K2K.

    TFTCentral: LG UltraGear Evo 39GX950B review

  • Dual-Mode has no true integer scaling. The reviewer saw an intermittent bug where the desktop split into sections after exiting, fixed by a screen reset. Grey banding is more visible at 330 Hz. VRR flicker appeared only in very dark scenes, mostly in Dual-Mode with large frame-rate swings.

    One review sample; intermittent bug and condition-dependent observations.

    TFTCentral: LG UltraGear Evo 39GX950B review

  • Height adjustment is stiff, and the screen wobbles slightly when adjusted or when the joystick is used. OLED care is limited to the screen saver and image cleaning, with no logo detection, taskbar detection or pixel shift.

    One review sample.

    TFTCentral: LG UltraGear Evo 39GX950B review

  • PCWorld measured a sustained 310 nits in SDR, just over 1000 nits on a 3 percent HDR window, 100 percent sRGB, 99 percent DCI-P3 and 93 percent AdobeRGB on the 39GX950B-B, with an average colour error of 2.53. At 143 PPI, text looks very sharp from about a metre away.

    Single test unit; colour error and brightness depend on settings and firmware.

    PCWorld: LG UltraGear evo GX9 review

  • PCWorld finds 165 Hz at 5120 x 2160 good for its class but blurrier than 240 Hz and faster monitors; the 330 Hz mode at 2560 x 1080 clearly sharpens motion but is judged a failure because of the resolution loss. The AI picture optimisation caused random colour temperature shifts, so the review recommends turning it off.

    Single review; no response time measurements were given, and the motion comments are observations.

    PCWorld: LG UltraGear evo GX9 review

Owner experiences and issues

Tags

2026OLED165HZ5K2KDISPLAYPORT-2-1

Compare

Sources

  1. LG UK: UltraGear evo GX9 39GX950B-B specifications
  2. LG Canada: 39GX950B-B specifications
  3. LG 39GX950B Owner’s Manual (English)
  4. LG 39GX950B Product Information Sheet (EU 2019/2013)
  5. TFTCentral: LG UltraGear Evo 39GX950B review
  6. HardForum: LG 39GX950B 39" 5120 × 2160 OLED 165 Hz ultrawide (page 2)
  7. PCWorld: LG UltraGear evo GX9 review