The Cooler Master Tempest GP27U is a premium 4k, 27-inch monitor. It features Mini LED backlighting with 576 local dimming zones, and as it's a high-end monitor, it has a ton of features for both productivity and gaming. It has a 160Hz max refresh rate that you can achieve over a DisplayPort connection, and it has HDMI 2.1 bandwidth that lets you take full advantage of the PS5 and Xbox Series X. Although it isn't officially certified by NVIDIA or AMD, both G-SYNC and FreeSync variable refresh rate (VRR) technology work. It has other features like a USB-C port that supports DisplayPort Alt Mode if you want to connect a laptop and has 90 W of power delivery. It also has a KVM switch that lets you control two devices with the same keyboard and mouse connected to it.
We tested the monitor using firmware 1.2 (version A), which was updated on Feb. 17, 2023, and certain aspects again with firmware 1.41 and 1.45. Firmware 1.2 fixes some of the issues that were part of the versions released for firmware 1.1 on Nov. 25 and Dec. 2, 2022, but it doesn't fix all the problems.
Our Verdict
The Cooler Master GP27U is an impressive overall monitor. It's excellent for the office thanks to its sharp text clarity, high peak brightness to combat glare, and excellent ergonomics that make it easy to adjust. It's also excellent for gaming as it has HDMI 2.1 bandwidth for console gaming, a fast response time and low input lag for a responsive feel, and VRR support to reduce screen tearing. It displays a wide range of colors in SDR and HDR, which is important if you want to watch content, and it also displays deep blacks thanks to its okay Mini LED local dimming. While it's also great for content creators, you'll have to calibrate it for the best performance.
- Incredible text clarity and image sharpness.
- Easily gets bright enough to fight glare.
- Excellent ergonomics.
- HDMI 2.1 bandwidth for console gaming.
- Colors wash out at an angle.
- Needs calibration for most accurate colors.
- KVM feature doesn't work well when switching sources.
The Cooler Master GP27U is an excellent office monitor. The 27-inch screen and 4k resolution help deliver a high pixel density, resulting in sharp text, and you can open multiple windows at once. You won't have issues using it in a bright room either, as it easily gets bright enough to fight glare, and the reflection handling is fantastic. It also has decent wide viewing angles and excellent ergonomics if you need to adjust your screen to show someone else.
- Incredible text clarity and image sharpness.
- Easily gets bright enough to fight glare.
- Excellent ergonomics.
- Productivity features like USB-C input.
- Colors wash out at an angle.
- KVM feature doesn't work well when switching sources.
The Cooler Master GP27U is excellent for gaming. You can take full advantage of the Xbox Series X or PS5 thanks to its HDMI 2.1 bandwidth and play games with sharp detail thanks to its 4k resolution. It also has VRR support to reduce screen tearing with both AMD and NVIDIA graphics cards. The input lag is very low, and this monitor has a quick response time that makes motion look smooth at any refresh rate. Lastly, it's a great choice for dark room gaming thanks to its okay local dimming feature for deep blacks.
- HDMI 2.1 bandwidth for console gaming.
- Quick response time at any refresh rate.
- FreeSync and G-SYNC support.
Okay Mini LED local dimming feature.
- More blooming when viewing off-center.
- KVM feature doesn't work well when switching sources.
The Cooler Master GP27U is very good for media consumption. Its 4k resolution helps result in sharp images with a ton of detail. Although it has a low native contrast ratio, its full-array Mini LED local dimming feature helps further improve the contrast for deep blacks, but with some blooming. However, while it has decent viewing angles, there's more blooming, and the image looks worse when viewing off-angle in a dark room, so it isn't good for watching content with a friend in a dark room.
- Incredible text clarity and image sharpness.
- Excellent ergonomics.
Okay Mini LED local dimming feature.
- More blooming when viewing off-center.
- Needs calibration for most accurate colors.
- KVM feature doesn't work well when switching sources.
The Cooler Master GP27U is great for content creators. The 4k resolution delivers sharp images, and the 27-inch screen is big enough to work comfortably. It's also a great choice for use in well-lit rooms because it gets extremely bright. While it has excellent ergonomics that make it easy to adjust and has decent viewing angles, the colors look washed out while viewing from the side, so it isn't good if you often need to share your screen with a client.
- Incredible text clarity and image sharpness.
- Easily gets bright enough to fight glare.
- Excellent ergonomics.
- Colors wash out at an angle.
- Needs calibration for most accurate colors.
- KVM feature doesn't work well when switching sources.
The Cooler Master GP27U is great for HDR. It gets very bright to deliver bright highlights and displays a wide range of colors with incredible color volume. While its native contrast ratio is low, it still delivers deep blacks thanks to its okay local dimming feature, and there's minimal blooming around bright objects. It also has fantastic gradient handling, meaning you won't see any banding with shades of similar colors, like in scenes with a sunset.
Okay Mini LED local dimming feature.
- Displays wide range of colors in HDR.
- Fantastic HDR peak brightness.
- Some tone mapping issues.
- Some settings locked in HDR.
- KVM feature doesn't work well when switching sources.
Changelog
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Updated May 07, 2025:
We rechecked the Local Dimming performance with firmware 1.45, but lowered the score because of how it compares to recent monitors. We also confirmed that the HDR Brightness is the same.
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Updated Dec 18, 2024:
Added that the LG 27GR95UM-B is an alternative that doesn't have any issues enabling VRR and HDR at the same time.
- Updated Feb 06, 2024: Added that the Dell Alienware AW3225QF has a better Contrast ratio.
- Updated Nov 21, 2023: Added that the Acer Nitro XV275K P3biipruzx has much better Accuracy Before Calibration.
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Differences Between Sizes And Variants
We tested the 27-inch Cooler Master Tempest GP27U, which is the only size and variant available for this model. It's one of two Mini LED monitors that Cooler Master has released to this point, with the Cooler Master Tempest GP27Q. You can see the differences between them below.
| Model Code | Size | Resolution | Max Refresh Rate | HDMI Type |
|---|---|---|---|---|
| GP27Q | 27" | 1440p | 165Hz | HDMI 2.0 |
| GP27U | 27" | 4k | 160Hz | HDMI 2.1 |
Our unit was manufactured in September 2022, and you can see the label here. The full serial number is CMIGP27FUSUS1223700041.
The review is with firmware 1.2 (version A), which Cooler Master updated on Feb. 17, 2023, though we retested the HDR Brightness and Local Dimming with firmware 1.41 (Sep. 2023) and firmware 1.45 (Aug. 2024). There were previous updates for firmware 1.1 on Nov. 25 and Dec. 2, 2022, each with their own issues. Essentially, ensure you have the firmware updated to the latest version for the best performance, but if you encounter anything different on your unit, let us know.
Popular Monitor Comparisons
The Cooler Master Tempest GP27U is a great overall monitor that strikes a balance between excellent gaming performance, great HDR, and also offering productivity features. It gets very bright and delivers brighter highlights and more vivid colors compared to the Samsung Odyssey Neo G8 S32BG85. Although it took some firmware updates to fix most issues, it mostly works as expected after the latest update. It's a cheaper option to the Samsung if you want a high-end 4k monitor for gaming that also delivers great HDR, but there still are some bugs like with its flickering, and it can be hard to find.
Also see our recommendations for the best 4k HDR monitors, the best HDR gaming monitors, and the best 4k gaming monitors.
The Cooler Master Tempest GP27U is better overall than the Gigabyte M28U. The Cooler Master delivers better overall picture quality thanks to its decent local dimming feature, which helps it get brighter and display deeper blacks. It also has higher HDMI 2.1 bandwidth than the Gigabyte, so your graphics card doesn't need to use compression to achieve high-frame-rate signals. On the other hand, the Gigabyte has better color accuracy, and colors don't wash out when viewing off-center like on the Cooler Master.
The Acer Nitro XV275K P3biipruzx and the Cooler Master Tempest GP27U are similar 27-inch, 4k monitors with Mini LED backlighting. However, there are a few differences between them The Acer has much better accuracy before calibration and slightly better reflection handling. The Cooler Master has better motion handling and lower input lag for a more responsive feel. The Cooler Master even has a KVM switch, ideal for multitasking, which the Acer doesn't have.
The Samsung Odyssey Neo G7 S32BG75 and the Cooler Master Tempest GP27U are both excellent 4k gaming monitors. They each have Mini LED local dimming that performs decently, and while the Cooler Master has lower native contrast, it still displays deep blacks like on the Samsung. The Cooler Master also has better motion handling and doesn't have the same bugs the Samsung has, like flicker with low frame rates, and it has a few extra features like a USB-C port and a KVM switch.
The Samsung Odyssey Neo G8 S32BG85 and the Cooler Master Tempest GP27U are both excellent 4k gaming monitors. The main difference is that the Samsung monitor has a much higher 240Hz refresh rate, making it future-proof for 4k gaming at a high frame rate. They each have Mini LED local dimming that performs decently, and while the Cooler Master has lower native contrast, it still displays deep blacks like on the Samsung. The Cooler Master also has better motion handling and doesn't have the same bugs the Samsung has, like flicker with low frame rates, and it has a few extra features like a USB-C port and a KVM switch.
We buy and test more than 30 monitors each year, all of which we purchase ourselves, without cherry-picked units or samples. We put a lot into each unbiased, straight-to-the-point review, and there's a whole process from purchasing to publishing, involving multiple teams and people. We do more than just use the monitor for a week; we use specialized, custom tools to measure various aspects and deliver objective, data-driven results. We also consider multiple factors before making any recommendations, including the monitor's cost, its performance compared to the competition, and whether it's easy to find.
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