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Our HDR benchmarking uses Portrait Displays’ Calman software. To learn about our HDR testing, see our breakdown of how we test PC monitors.
The X27 X1 must be switched manually to HDR mode when an HDR10 signal is present. It also offers HDR emulation for SDR content, which is a rarity in this segment.
HDR Brightness and Contrast
I measured both field and window patterns and found the 25% pattern to be the brightest at over 445 nits. This meets the HDR400 spec and shows that the X27 X1 is using variable brightness. A full field pattern measured around 273 nits. HDR has plenty of depth and impact with perfect blacks and infinite contrast. Its peak level is about average for the category.
Grayscale, EOTF and Color
I measured HDR Auto and HDR-1000(Max) and found them to be identical. The charts above represent Auto. Grayscale has a slight warmth with errors around 5dE at brightness steps above 50%. The EOTF tracks a bit dark below 30% and hits the reference at all other points. The tone map transition is slightly smoothed and happens at 60%, which is correct for the measured white and black thresholds. This is excellent performance.
In the color test, the X27 X1 sticks to the hue targets for all colors in both DCI-P3 and BT.2020 charts. Most points are slightly oversaturated, which is typical of the HDR monitors I’ve tested. HDR color is very accurate here. In the BT.2020 test, color runs out at 90% red, 75% green, and 95% blue. This is also typical of Quantum Dot displays.
Test Takeaway: The X27 X1 has average HDR brightness with an impactful image that is color accurate. It uses variable brightness and slightly oversaturated color to effectively add impact to the image. It is on par with the better HDR OLED monitors I’ve tested.
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