LG 27GX790A-B  Monitor Review

The monitor has a simple yet sleek design. Its understated appearance fits well into an office or gaming environment. However, the display bottom has a small shiny strip, which could be distracting for some in certain lighting conditions, as it's quite reflective.

The build quality is excellent. While the housing is plastic, it's quite solid, with minimal creaking or flex. However, there is a bit of a gap between the bezel and the display at the bottom of the monitor.

The ergonomics are great. You can make any common adjustment, including rotating the monitor vertically, and most adjustments offer a wide range of movement. The stand has a cutout for cable management, which you can also see up close.

While the top of the stand is plastic, there's metal underneath on the base, which adds extra weight.

The housing height results include the small bar below the screen.

There's a joystick to control the on-screen display and turn the monitor on and off.

• DisplayPort cable
• HDMI cable
• USB-B to USB-A cable
• Power supply and cable
• User documentation

The LG 27GX790A has a near-infinite contrast ratio to display perfect blacks next to bright highlights.

This monitor doesn't have a backlight, so it doesn't require a local dimming feature. However, with a near-infinite contrast ratio, there isn't any blooming around bright objects, and it's the equivalent of a perfect local dimming feature. We still film these videos on the monitor so you can see how the screen performs and compare it with a monitor that has local dimming.

Settings

• Picture Mode: Gamer 1 (after calibration)
• Brightness: 100
• Peak Brightness: High

The SDR brightness is acceptable. It's darker than many OLEDs, but you can still easily see it in a moderately lit room, though it doesn't overcome bright glare. If you want something brighter, you can also look into the newer LG 27GX700A-B, which uses the RGB Tandem OLED panel.

You can set Peak Brightness to 'Low' or 'Off,' which results in more consistent brightness across different content, but they're dimmer. You can see how these modes affect brightness levels in more detail below:

Settings

• Picture Mode: Gamer 1
• Brightness: 100
• Peak Brightness: High
• Smart Energy Saving: Off

The HDR brightness is decent. It gets bright enough to fight glare in most well-lit rooms, and it also makes small highlights pop against the rest of the image. However, it doesn't sustain the brightness with larger highlights. It follows the PQ EOTF curve well, though it has a slow roll-off near peak brightness, so highlights don't get as bright as they could.

If you set Peak Brightness to 'Low' it isn't as bright, as you can see below:

If Peak Brightness is 'Off,' it's far less bright; its maximum brightness is 187 cd/m² and 185 cd/m² at both 2% and 100% window sizes, respectively, and its PQ EOTF tracking is much worse.

The gray uniformity is excellent, and there aren't any noticeable issues with bright and mid-tone grays. However, there's banding with dark grays, which you can see with 15% gray. This is noticeable depending on the content, but it's not the worst case of this vertical banding that's a common issue with WOLEDs.

The black uniformity is outstanding, with a uniform black level across the screen.

The accuracy before calibration in the 'sRGB' Game Mode is great. However, you need to have the monitor's firmware updated to version 3.04, 2.04 or newer, as the accuracy was worse before the update. It locks colors well to the sRGB color space, and has good color accuracy, but the white balance is off. It also has bad gamma tracking, with most content being too bright.

Other modes have the same inaccuracies, but with more oversaturated colors. If you decide to use the 'sRGB' mode, the following settings are locked:

• Game Adjust: Black Stabilizer
• Picture Adjust: Sharpness, Gamma, Color Temperature, RGB control, Six Color, Black Level

The accuracy after calibration is fantastic. However, the brightest parts of scenes are too dark.

The SDR color gamut is fantastic. It displays virtually all of the sRGB color space used by most desktop and web content. It has good coverage of the wider Adobe RGB color space, but it can't display the full range of greens in that color space and oversaturates reds, so it isn't ideal if you need to edit in Adobe RGB.

The HDR color gamut is fantastic. It displays nearly all colors in the common DCI-P3 color space, though a more limited range in Rec. 2020, and colors are fairly accurate.

The HDR color volume is great. It displays dark colors well, but it doesn't display bright colors as vividly as on QD-OLED displays.

The horizontal viewing angle is incredible. Although it technically isn't perfect, you visually won't see any inconsistencies when viewing from the sides or if you sit close to the screen.

The LG 27GX790A has okay text clarity. When using ClearType, it has less fringing than other 27-inch, 1440p OLEDs with an RWBG subpixel layout. However, it's still not as sharp as RGB subpixel displays like IPS and VA panels.

Without using ClearType, there's no fringing, but letters are harder to read. These photos are in Windows 10, and you can also see them in Windows 11 with ClearType on and with ClearType off.

The direct reflection handling is great. The matte coating absorbs light well and minimizes mirror-like reflections. However, it spreads light out instead.

The black levels remain low even in a bright room, which is great. However, they still rise a bit, so you don't get the same perfect blacks as in a dark room.

This monitor has some reflected light in a bright room, but it isn't overly distracting. Although it doesn't have strong reflections coming directly off the screen, the coating spreads light out instead.

The gradient handling is remarkable, and there's almost no banding.

On top of FreeSync VRR and G-SYNC compatibility, this monitor also supports HDMI Forum VRR.

The LG 27GX790A has remarkable motion handling across its VRR range. There's minimal blur or smearing with fast-moving objects, and it remains consistent as the refresh rate drops. Any blur at low refresh rates is persistence blur.

The refresh rate compliance is outstanding. With a near-instantaneous response time, it makes full-color transitions before drawing the next frame.

The CAD at the max refresh rate of 480Hz is outstanding. Motion looks incredibly sharp without any noticeable blur.

The CAD at 120Hz is incredible. It has a near-instantaneous response time, and although it isn't perfect, there isn't noticeable smearing or inverse ghosting.

The CAD at 60Hz is fantastic. Any noticeable blur is persistence.

This monitor doesn't have a black frame insertion feature to reduce persistence blur.

This monitor has bad VRR flicker with changing frame rates, which is most distracting in dark scenes.

The backlight isn't technically flicker-free because it has a dip in brightness that corresponds to the 480Hz refresh rate.

The LG 27GX790A has low input lag for a responsive feel. However, you need to update the firmware to version 3.04, 2.04 or newer to get the lowest 60Hz input lag. The 60Hz input lag was much higher before the update, but the input lag at 120Hz and 480Hz didn't change with the update.

With HDMI 2.1 bandwidth, this monitor can take full advantage of the PS5, but it downscales 4k signals to 1440p.

With HDMI 2.1 bandwidth, this monitor can take full advantage of the Xbox Series X|S. It downscales 4k signals, which is useful because the Xbox only supports HDR in 4k.

These results are with an AMD RX 7800 XT. When we test with an NVIDIA graphics card using driver version 576.52, it reports the DisplayPort transmission bandwidth is UHBR10 (40.00 Gbps). 

This monitor works well with macOS. If you're using a MacBook the monitor goes to sleep when you close the lid. When you reopen the lid, windows return to their original positions on the monitor. Both VRR and HDR work well and look good.

The LG 27GX790A has a few extra additional features, including:

• Crosshair: Adds a virtual crosshair that your system won't detect.
• DTS Headphone:X: Simulates surround sound audio with headphones. The headphone jack is also a mic input.
• FPS Counter: Displays the frame rate of your source.

Like most OLED displays, there are also a few settings to help reduce the risk of burn-in:

• OLED Image Cleaning: Runs a complete image refresh cycle after every four hours of use and starts when you turn the monitor off or enter the power saving mode. It takes about 10 minutes to finish.
• OLED Screen Move: Moves the image by a few pixels to one side to help reduce the risk of burn-in. If you have it enabled, you can choose from three different movement patterns. You can also turn it off if you prefer.
• OLED Screen Saver: Automatically turns the screen off when there's inactivity.

Burn-in can occur with constant exposure to the same static elements over time, so the best ways to reduce the risk of burn-in is by watching varied content, hiding the taskbar, and using a black background.

You can find more information about the monitor's OSD in the Owner's Manual, which is available on the 27GX790A-B's support page if you click the "Manuals & Software" tab.