The XG320U has an automatic HDR mode that switches on when an HDR10 signal is detected. This engages an effective dynamic contrast feature as well. There are no image adjustments available, but as I found out, they are not needed.
HDR Brightness and Contrast
The XG320U is certified for DisplayHDR 600, but I couldn’t quite reach that figure in my tests. Measuring both window and full-field patterns yielded the same result. It’s close at over 543 nits, but not quite 600. But brighter HDR is not necessarily better. It’s the black levels and contrast that make the difference. ViewSonic has no trouble there with a class-leading black level of 0.0308 and a very high 17,634.3:1 ratio. That puts it among the very best of the edge backlight HDR displays I’ve tested. The XG320U delivers a very impactful HDR image.
Grayscale, EOTF and Color
The XG320U’s HDR mode is a simple one; there are no options, but if you prefer an accurate image, you’re good. HDR grayscale tracking is visually perfect with all errors under 2dE. The EOTF tracks a little dark at the bottom and a little light as it approaches the tone-map transition at 65%. I had no trouble discerning fine shadow or highlight detail. Nothing was blown out, overly bright or overly dark.
Since the XG’s gamut is so large, I ran the HDR color test against DCI-P3 and Rec.2020. Its tracking follows the hue targets as it should and over-saturates the inner points like most HDR monitors do. HDR color pops brilliantly in all content making the XG320U a fun gaming and entertainment display. Whether you play PC or console games or stream your favorite shows, there is no shortage of color from this ViewSonic.