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
The U27M90 is a very bright monitor for both SDR and HDR material. In SDR mode, the max output is over 437 nits which is enough for outdoor use. In my sunlit office, 200 nits is plenty.
The panel’s native contrast is around 1,030:1, which is typical IPS performance. Local Dimming set on High ups that number to just over 6,000:1. I used the feature for all my hands-on SDR tests as it enhanced contrast and depth with no downsides like crushed detail or image pumping. Sony has engineered its dynamic contrast feature very well here. The U27M90 can easily match up to a good VA monitor with Local Dimming engaged.
After Calibration to 200 nits
I calibrated the Game 1 mode and got the same contrast results with brightness set to 200 nits. Again, this is the panel’s native state without Local Dimming turned on.
The ANSI number is only 0.5 off the static one, which indicates the best possible quality of components and manufacturing. This is literally as consistent as a display can be. Though the U27M90 is a premium purchase at $899, it outperforms monitors costing much more like the Acer X27.