To read about our monitor tests in-depth, please check out Display Testing Explained: How We Test PC Monitors. We cover brightness and contrast testing on page two.
Uncalibrated – Maximum Backlight Level
Cooler Master claims 600 nits for the GP27Q, but I measured just under 500. And it’s just as well. No SDR image will benefit from such a high peak output level unless you’re viewing it in bright sunlight. In an indoor environment, 500 nits is painfully bright. The issue I have is that lower levels are hard to achieve. The GP27Q goes down to 55 nits which is good, but each click of the slider changes the setting by 5 to 7 nits. It’s hard to hit a specific spec like 200 or 120 nits right on the head.
Black levels are fairly high, making the default contrast ratio high as well. 765:1 is below average among IPS panels. You’ll want to reduce the local dimming for SDR content to get the best possible image.
After Calibration to 200 nits
Calibration improves contrast to 880.1:1, but I still prefer the image with local dimming on low. Contrast performance is still below average in the IPS monitor category.
ANSI contrast is almost identical to static at 888.7:1. This is a point in favor of Cooler Master’s quality control which is excellent in all respects. Like the static test, local dimming renders the ANSI value infinite since the black zones have the backlight turned off.
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Also if you want the 4k version of this monitor for only $899 you can buy the ktc m27p20 pro off amazon.
KTC is the OEM that makes these monitors for Cooler Master.
KTC also sells a 27 1440p model similar to the one reviewed here but with a VA panel for $500.