To learn about our HDR testing, see our breakdown of how we test PC monitors.
Given the caveats we talked about earlier, the GFI27QXA’s HDR support is best described as partial. You can use it for movie-watching but when gaming, you have to give up adaptive sync which is not a good idea when frame rates are hovering around 75 fps.
The GFI27QXA will automatically recognize an HDR10 signal and switch over, but it inherits the brightness setting from SDR, then locks out the image controls. If you want bright HDR, you must max the brightness slider before changing signals. Maximum output is just OK at 370.6695 nits. But with a respectable black level, contrast is the same value we saw in SDR mode, 1236.1:1. We tried the Dynamic Luminous Control option, but it only reduced contrast by raising the black level. There is no usable dynamic contrast option available. Short of a FALD backlit display, your best bet is the Asus or ViewSonic screen which employs an effective variable contrast feature to push dynamic range higher.
Grayscale, EOTF and Color
The GFI27QXA’s color accuracy is very good in HDR mode. There are no adjustments available but that’s not a problem as there were no visible errors in grayscale tracking. The EOTF luminance curve runs a bit dark until its soft transition to tone-mapping at 55% brightness.
Color tracking is very similar to what we saw in SDR mode. Red is slightly over-saturated, but the magenta hue error is a bit less. Visually, there is little difference. This is excellent performance and we’re pleased to see a monitor that truly covers the full DCI-P3 gamut.