AOC Gaming U27G4R review: Versatile gaming monitor at a great price

With the AOC Gaming U27G4R unveiled in May 2025, the manufacturer has an extremely exciting gaming monitor on offer. After all, the 27-incher not only supports a 4K resolution of 160 Hz, but also switches to Full HD at 320 Hz at the touch of a button. And at an almost unbeatable price. Our test.

Technical data

AOC Gaming U27G4R review: Inconspicuous picture giant

• Simple black plastic casing
• quick, tool-free assembly
• good workmanship

The AOC Gaming U27G4R is an inconspicuous gaming monitor. No extravagant RGB lighting, no frippery, just a focus on the essentials: The picture quality. The scope of delivery is correspondingly modest, as the monitor is also part of the manufacturer’s budget range.

Stand, bracket, power cable, manual and display. That’s all you get. No HDMI or DisplayPort cables, no other accessories. Okay, most people should have it lying around at home anyway.

The monitor itself is then also quickly assembled and fortunately without tools. Screw on the stand, insert it into the back of the monitor, set it up and get started. That’s how it should be.

The AOC Gaming U27G4R itself is kept simple. A black plastic case with a red cable outlet on the stand and a red ring on the back provide pleasant details. The display is frameless on three sides, with only the lower frame measuring around 1.8 centimeters in height.

The AOC logo can be found in the center of the frame, while the labels for the controls can be found on the right edge. The rather large stand is based on a hexagonal design with rounded edges, on which the mouse and keyboard can also be placed to save space. In other words, a simple gaming monitor. There is nothing to complain about in terms of workmanship and there are no gaps to be found.

Connections, features and operation

• 2x HDMI 2.1, 1x DP 1.4
• USB hub, but no USB-C
• Dual-frame technology

In terms of connectivity, the AOC Gaming U27G4R is well positioned. A total of three ports are available for image display: Thanks to two HDMI 2.1 ports, the monitor is also perfectly suited for the latest gaming consoles such as PS5, Xbox Series X/S or Nintendo Switch 2 and displays content on consoles in 4K resolution at 120 Hz (4K/160 is available on the PC). There is also a DisplayPort 1.4 connection.

AOC also provides the display with two USB hubs: On the bottom you will find a USB-A 3.1 port and a USB-B port. Two additional USB-A 3.1 ports are easily accessible on the right side.

The selection is rounded off by a headphone connection, but unfortunately the monitor does not have a USB-C port. A KVM switch is also consistently omitted.

A special feature of the AOC Gaming U27G4R is undoubtedly the dual-frame technology. At the touch of a button, you can switch between 4K UHD at 160 Hz or Full HD (1,920 x 1,080 pixels) at 320 Hz. The latter mode is of course particularly exciting for competitive gamers who want the fastest possible picture.

To ensure this, the U27G4R with its matte Fast IPS panel has a response time of 1 ms when switching from gray to gray. Adaptive Sync is used as synchronization technology, while the maximum brightness of 400 cd/m² guarantees VESA DisplayHDR 400 certification.

AOC Gaming also provides the monitor with various picture modes. These include a sniper mode, a crosshair, black stabilizer, low blue mode, a fps display as well as picture-in-picture and picture-by-picture modes.

The ergonomic options are also suitable: The AOC Gaming U27G4R is height-adjustable by 130 mm, can be tilted between 3.5 degrees and 21.5 degrees, swiveled by up to 30 degrees in both directions, rotated and also moved vertically thanks to the pivot function.

Somewhat fiddly operation

• Controls difficult to recognize
• Tidy OSD
• Practical G-Menu software

The AOC Gaming U27G4R does not rely on a comfortable joystick for operation, but rather on five buttons on the right edge of the underside, which works quite well in practice, but seems a little fiddly. In addition, the lettering on the front is difficult to read.

The left button takes you to the on-screen display (OSD for short), which is at least very tidy and clear. It provides information about important parameters such as resolution and frame rate at the top and guides you through the menu on a total of seven tabs.

In the game settings, you can also use the dual-frame technology and switch from 4K/160 to 1080p/320 at the touch of a button. Various game modes, adaptive sync and other settings such as sniper mode can also be found here.

In the “Image” menu, you can then adjust the image quality in terms of brightness, contrast, gamma value and much more. In other words, everything you would expect from most monitors. Fortunately, the AOC Gaming U27G4R also uses the manufacturer’s G-Menu. This is free software in which you can also adjust the settings. Of course, this increases the ease of use immensely. A clear recommendation.

Picture quality of the AOC Gaming U27G4R

• strong picture quality
• low input lag
• very good color reproduction; but not ex works

Fortunately, the AOC Gaming U27G4R impresses exactly where it really matters: in terms of image quality. The flat, matte Fast IPS panel offers excellent viewing angles and offers a high pixel density of 163 pixels per inch in 4K resolution, which ensures razor-sharp images and harmonious details.

I really liked the picture quality in 4K gaming use. Details are crisp and sharp and the colors are also pleasing. After all, the color space coverage of 124.7 percent sRGB and 95.9 percent DCI-P3 is also very good.

For gaming use, the AOC Gaming U27G4R also offers a low-input lag mode (LIL mode), which can be activated in the OSD. You should definitely do this for gaming, as it noticeably reduces latency, which ensures a smoother, faster gaming experience. However, this is only possible if you deactivate Adaptive Sync in the menu, otherwise Low Input Lag is grayed out.

Especially in competitive games, the LIL mode is preferable in my opinion, which almost negates the delay of the input devices. Excellent! In terms of response time, there are also various modes to choose from, including Normal, Fast, Faster and Fastest. In 4K resolution, I was able to achieve the best results with the “Faster” setting.

However, the monitor is not set ideally by default. The white balance is clearly too warm, which distorts the colors. However, this can be easily changed via the OSD or G-Menu, which noticeably improves the picture quality. Also commendable: AOC Gaming provides the monitor with dedicated sRGB and DCI-P3 modes, which are particularly suitable for color-critical work.

While the peak brightness does not reach the full 400 nits in SDR mode, it is quite impressive with the HDR profile activated. With HDR enabled, I was able to achieve a brightness of around 540 nits.

Is Dual Frame worth it?

4K with 160 Hz or 1080p with 320 Hz. And all at the touch of a button. While the dual frame technology of the AOC Gaming U27G4R is certainly nothing new – we have already seen similar technologies in the ASUS ROG Swift OLED PG32UCDP, for example – it is definitely an exciting feature for anyone who enjoys competitive gaming.

How well and easily the modes can be switched depends on the game in question. In titles such as Valorant, The Finals or Fortnite, I was able to switch modes during the test, even in an ongoing round, and immediately benefit from the high frame rate.

In other games, however, such as F1 25 or DOOM: The Dark Ages (our test), changing the picture mode led to a faulty display. The only thing that helped here was to close the game, switch to Full HD mode and then restart the game.

In 1080p with 320 Hz, the monitor then manages without any ghosting, but the pixel density also drops noticeably, which can of course be seen in the picture. This is of course acceptable for esports gaming, but I prefer the higher resolution even in fast-paced shooters.

Lab test of the AOC Gaming U27G4R

As always, I also took a close look at the AOC Gaming U27G4R in the lab. The Datacolor SpyderX Elite was used to test various parameters of the monitor. For the test, I first reset the display to the factory settings and tested the standard mode – so if you tweak the OSD yourself, you can still get a lot out of it.

In terms of color space coverage, the AOC Gaming U27G4R meets the manufacturer’s specifications and achieves over 100 percent sRGB and around 95 percent DCI-P3.

The color fidelity is also surprisingly strong: With an average value of Delta E 1.03, the monitor achieves an outstanding value, making it excellent for color-critical work. If you use the sRGB or DCI-P3 mode, you can even achieve a deviation of Delta E <1. Absolutely excellent.

However, the other measured values are not quite as excellent. The monitor still delivers good brightness values of 385.9 cd/m², but the contrast ratio of 1,000:1 is not quite achieved at maximum brightness, while the white point deviates significantly. Switching to “Standard” mode significantly improves the display here.

The U27G4R maintains the gamma curve very well, although the set value in the OSD of gamma 2.2 is more like 2.3 in reality. Here you can select various settings in the menu up to a maximum of gamma 2.6.

The homogeneity of the picture is at a good level. However, there are deviations of up to Delta E 5.5 in the upper left rectangle at maximum brightness, which decreases when you reduce the brightness, especially in the uniform representation of the colors.

The situation is similar with luminance homogeneity, although the deviations here tend to be in the lower third. At 100 percent brightness, there are deviations of up to 10 percent or 37.5 cd/m² compared to the center of the screen, which decrease when you reduce the brightness.

In my opinion, the ideal brightness of the AOC Gaming U27G4R is between 75 percent and 78 percent, where you get the best picture quality.

AOC Gaming U27G4R review: Conclusion

Modern connections, great 4K picture quality, almost non-existent latency and all this at a great price: the AOC Gaming U27G4R offers an enormous amount for the price. Especially those who enjoy competitive gaming will be pleased with the monitor’s very good Fast IPS panel and will also make use of the dual-frame technology, which significantly improves the frame rate in 1080p.

PC and console gamers alike will get their money’s worth here and receive a fast, high-resolution monitor with practical features. Whether you like the simple design or not is certainly a matter of taste. The USB hub is also very practical, although it unfortunately lacks USB-C.

Anyone looking for a fast, reliable and attractively priced 4K gaming monitor is guaranteed to be happy with the AOC Gaming U27G4R.