AOC Q27G40XMN  Monitor Review

The AOC Q27G40XMN has a straightforward design, with an all-black plastic body and some red accents on the back. Its appearance does not truly stand out, and it fits well into any environment.

The build quality is okay. The plastic materials feel solid without a lot of flex or creaking, but the bottom bezel feels cheap and flexes without much pressure. However, the biggest downside is that the monitor wobbles a lot on its stand and takes some time to recover. It's also very hard to adjust the screen on the stand, as it requires a good amount of force.

The AOC Q27G40XMN has poor ergonomics. You can only tilt it, but even at that, it's very hard to do so and you need some force to adjust it. The stand doesn't offer anything for cable management either.

The stand takes up minimal space, but it doesn't hold the screen well, as it wobbles easily.

If you want an even larger display, take a look at the Dell Alienware AW3225DM.

There are four buttons to control the on-screen display, act as shortcuts, and change inputs, and there's a power button. They feel solid and are easy to learn how to use.

• DisplayPort cable
• HDMI cable
• Power cable
• User documentation, including calibration report

The contrast ratio is excellent. Even without local dimming, it displays deep blacks against bright highlights. Using local dimming greatly improves the contrast, but because it locks the brightness to the max, we couldn't measure the contrast ratio with a screen brightness of 100 cd/m² like we do with other monitors. As it maintains a low black level even with this high brightness, this is why the contrast is so high.

The local dimming feature has 1,152 dimming zones and performs very well. The 'Strong' setting really improves the contrast ratio by helping the monitor display deep blacks against bright objects. It keeps details well, like in scenes with a star field, and there isn't much blooming in real content, like subtitles, although the test video has more blooming. Fast-moving objects also transition between the dimming zones smoothly, and there isn't any noticeable flicker.

As using Local Dimming locks the brightness to the max, bright scenes are really bright, reaching around 500 nits in SDR and 900 nits in HDR. There's no way to lower the brightness.

The 'Strong' Local Dimming setting performs best for watching content in SDR, but not for browsing the web. This is because some desktop icons on a black background look oversaturated compared to them on a bright background, which doesn't happen with it set to 'Medium.' That said, you may prefer not using Local Dimming when browsing the web, as it locks the brightness to the max.

There's also a bug when using the 'Strong' Local Dimming setting in the 'DisplayHDR' HDR Mode. Content looks overbrightened and desaturated, and it stays like this even when switching back to SDR or turning the monitor on and off again. The only way to stop the issue is by resetting the monitor. We don't recommend using the 'Strong' Local Dimming setting with the 'DisplayHDR' HDR Mode, and it's better to use 'Medium' instead because it doesn't have this bug. That said, this issue doesn't happen in any of the other HDR Modes.

Our unit was manufactured in February 2025, but there are reports that units manufactured in March 2025 and later don't have this same bug. You can share your unit's label in the Comments section whether you're experiencing the same bug or not.

Settings

• Gaming Mode: Standard (after calibration)
• Brightness: 100 (locked with Local Dimming enabled)
• Eco Mode: Standard
• Local Dimming: Strong

The AOC Q27G40XMN has excellent SDR brightness. It easily gets bright enough to fight glare in a well-lit room. Using Local Dimming locks the brightness to its max, but there's a variation in brightness between different content. If that bothers you, disabling Local Dimming results in a more consistent brightness, and it still gets bright at around 450 cd/m². You also need to disable Local Dimming if you want the lowest minimum brightness.

Settings

• HDR Mode: DisplayHDR
• Local Dimming: Medium
• Brightness: Max (locked)

The HDR brightness is incredible. It makes small highlights pop, and even though it doesn't sustain this brightness with larger highlights, it still gets bright enough to fight glare in a well-lit room. However, it has terrible PQ EOTF tracking, as most content is darker than intended, and it has a very slow roll-off at the peak brightness, so it doesn't let all highlights get the brightest possible. Setting Local Dimming to 'Strong' results in better PQ EOTF tracking, but as explained in Local Dimming, the 'Strong' setting has a bug with the 'DisplayHDR' HDR Mode that makes content look washed out.

The 'DisplayHDR' HDR Mode is only available when the monitor receives an HDR signal, which locks all picture settings except for Local Dimming. 'DisplayHDR' has a similar PQ EOTF to the other HDR Modes, but 'DisplayHDR' has the best colors.

The gray uniformity is impressive. Although the edges are darker, the rest of the screen displays colors uniformly, and it has minimal dirty screen effect in the center. It also has great 5% gray uniformity.

The black uniformity with Local Dimming disabled is disappointing. There's cloudiness throughout, and even though it looks worse in the picture than in person, it's still noticeable. Using Local Dimming greatly improves the uniformity by removing these issues, and it displays an even black level throughout.

Settings

• Color Space: sRGB
• Gaming Mode: Standard

The accuracy before calibration in the sRGB mode is fantastic. It locks colors well to the sRGB color space, though some are undersaturated and inaccurate. It also has some white balance issues, particularly with brighter shades, but it's still great overall. The color temperature is close to the 6,500K target, and gamma is good overall, but dark scenes are too dark, and other scenes are too bright.

There are different picture modes available, depending on the combination of settings you choose. The regular picture mode setting is called Gaming Mode, of which the 'RTS,' 'Racing,' and 'Gamer' modes all perform nearly the same and lock the Eco Adjustment, HDR Mode, and Color Space settings. By selecting the 'Standard' Gaming Mode, you can change these settings, like selecting the 'sRGB' Color Space. 

You can also use any of the Eco Adjustment picture modes with Gaming Mode on 'Standard,' Local Dimming disabled, and Color Space on 'Panel Native.' These Eco Adjustment modes perform the same with varying levels of brightness, except for 'Reading,' which is a grayscale mode. Besides 'Standard,' these Eco Adjustment modes lock the Brightness and Contrast settings. 

Using the sRGB mode locks the listed settings below. You'd have to use a less accurate mode to get access to these settings.

• Shadow Control
• Game Color
• Contrast
• Gamma
• Eco Adjustment
• Color Temp.
• Red, Green, Blue
• HDR Mode
• LowBlue Mode

Settings

• Color Space: Panel Native
• Gaming Mode: Standard

The AOC Q27G40XMN's accuracy after calibration is remarkable. Calibrating it fixes most issues, and any remaining inaccuracies are hard to notice. Using the 'Standard' Gaming Mode unlocks all OSD settings, including HDR Mode and Color Space.

The SDR color gamut is remarkable. It displays a wide range of colors in the sRGB and Adobe RGB color spaces. Although some colors, like red and blue, are oversaturated in Adobe RGB, you may be able to avoid this issue with a color-managed app.

The HDR color gamut is great. It displays a wide range of colors in DCI-P3 and Rec. 2020, with minimal inaccuracies in each.

The HDR color volume is excellent. If you set Local Dimming to 'Medium,' it displays dark colors well, but really struggles with bright colors. We test this with a bright 75% stimulus, but it displays better colors with a 50% stimulus, which represents darker colors.

Using the 'Strong' Local Dimming setting in the 'DisplayHDR' HDR Mode results in a better tested color volume, but as explained in Local Dimming, the image looks washed out with the combination of these settings.

The AOC Q27G40XMN's horizontal viewing angle is disappointing. The image quickly washes out from the sides, making it a bad choice if you want to share your screen with someone next to you.

The text clarity is good. Using Windows ClearType (top photo) helps make letters look bolder. 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 decent. It spreads light out and makes some images look warped, but it doesn't have strong mirror-like reflections, either.

This monitor has minimal black level raise in bright rooms. Although the black levels aren't as good as they are in a dark room, they still look fairly deep.

This monitor has distracting reflections in really bright rooms. Although it spreads light out, a lot is still reflected back, creating distracting glare.

The gradient handling is remarkable. There's minimal banding between shades of similar colors.

There are reports online that people can't reach a 180Hz refresh rate with 8-bit color depth and full dynamic range RGB 4:4:4 over DisplayPort. We experienced the same issue with our NVIDIA GeForce RTX 5070 Ti graphics card as we had to use 4:2:2 subsampling to get the 180Hz refresh rate, or drop down to 170Hz to get RGB 4:4:4. This means the input is limited to DisplayPort 1.2 bandwidth. However, we didn't experience the same thing with our AMD Radeon RX 7800 XT graphics card, as we were able to get a 1440p @ 180Hz 8-bit full range RGB signal, despite its bandwidth limitations.

Due to other bandwidth limitations, the max refresh rate is lower with 10-bit signals.

The AOC Q27G40XMN has great motion handling across its VRR range. The 'Faster' Overdrive setting has minimal blur, but there's still smearing and inverse ghosting as the refresh rate drops. The 'Fastest' Overdrive has such high CAD that it passes the limits of the graph, which you can see with an alternative graph using a different scale.

The refresh rate compliance is great. Its response time isn't fast enough to make most full color transitions before the monitor draws the next frame with high frame rates.

The CAD at the max refresh rate of 180Hz is great. Although there isn't too much noticeable blur, it still has black smearing with dark objects, which is typical of VA panels. The 'Faster' Overdrive performs the best overall, but 'Fast' has less inverse ghosting, at the cost of added blur.

The CAD at 120Hz is great. Like at the max refresh rate, there isn't much blur with fast-moving objects, but it still has some inverse ghosting and smearing with the 'Faster' Overdrive setting. You can use the 'Fast' Overdrive setting if you want less inverse ghosting, but it has more overall blur.

The CAD at 60Hz is decent. There's more smearing and blur than at higher refresh rates, but the 'Faster' Overdrive setting still performs the best.

The AOC Q27G40XMN doesn't have a backlight strobing feature to reduce persistence blur.

The AOC Q27G40XMN has noticeable VRR flicker with changing frame rates. It looks worse in person than in the video or what the score presents. There's flicker throughout the entire image, including in bright areas, which can be distracting when there's a big change in the frame rate.

The AOC Q27G40XMN's backlight is flicker-free as it doesn't use pulse width modulation to dim its backlight.

The AOC Q27G40XMN has very low input lag for a responsive feel. You need to enable Adaptive-Sync or Low Input Lag to get the lowest input lag, as it's higher with Low Input Lag off:

• 180Hz: 15.0 ms
• 120Hz: 13.5 ms
• 60Hz: 22.1 ms

Although you can't use Low Input Lag with VRR enabled, the input lag remains equally low even with Adaptive-Sync enabled on the monitor.

As we test input lag over DisplayPort with our PC that has an NVIDIA graphics card, we had to use chroma 4:2:2 to get a 180Hz signal. However, when testing the 120Hz input lag, we noticed there's no difference in performance between 4:4:4 and 4:2:2.

As this monitor lacks HDMI 2.1 bandwidth, it can't take full advantage of the PS5 or PS5 Pro.

As the AOC Q27G40XMN lacks HDMI 2.1 bandwidth, it can't take full advantage of the Xbox Series X|S. It at least downscales a 4k @ 60Hz signal, which allows you to use HDR, as the Xbox doesn't support HDR with 1440p or 1080p signals. We did experience some issues when changing settings on the Xbox, as it would become unresponsive, but this shouldn't be an issue if you don't play around with the settings.

Despite being advertised as DisplayPort 1.4, the AOC Q27G40XMN supports HBR2 (5.4 Gbps per lane) over DisplayPort, which is the bandwidth of DisplayPort 1.2. This is despite the fact that it still supports 1440p @ 180Hz 8-bit RGB signals over DisplayPort with an AMD PC, which is theoretically not possible with DisplayPort 1.2. We confirmed this using CRU; by changing the Timing to 'Exact reduced,' the pixel clock is 709MHz, which is under the max clock speed of 720MHz of HBR2. We even opened up the monitor to see if any part numbers confirmed which DisplayPort version it has, but that did not give us this info.

Tested with: M2 MacBook Pro (Sequoia 15.4.1)

This monitor works well with macOS. Colors look oversaturated in SDR, but colors are more accurate in the 'DisplayHDR' HDR Mode once you enable HDR. VRR works well over DisplayPort, but only up to 170Hz, and it isn't available over HDMI. If you're using a MacBook without any power plugged into the laptop and close the lid, the monitor goes to sleep. However, plugging the laptop into power allows the monitor to stay on, and you can continue using the MacBook with any peripherals plugged in. When reopening the lid or waking the laptop up from sleep, windows return to their original positions.

The AOC Q27G40XMN has a few extra features in the OSD, including:

• Shadow Control: Adjusts the black levels so that it's easier to see opponents in dark scenes.
• Game Color: Controls the saturation of colors.
• Dial Point: Adds a virtual crosshair on the screen that your game's anti-cheat tool won't detect.
• Sniper Scope: Zooms in on the center of the screen.
• Frame Counter: Displays the current frame rate of your source.
• LowBlue Mode: Lowers the blue light output to help reduce eye strain.

You can learn more about the OSD in the user manual.