The XG321UG’s Mini LED backlight delivers tremendous light output in HDR mode. It is the second brightest computer monitor I’ve yet measured. Only the Asus PA32UCG, a $5,000 professional reference display, is a hair brighter.
HDR Brightness and Contrast
In this group, the XG321UG takes the HDR brightness contest over the PG32UQX by a comfortable margin. One might be able to tell the difference, but at that level, the screen is too bright to view directly when a full white field pattern is displayed. To get the highest possible reading, I measured a 25% window pattern. A full field measured around 1,300 nits which is very impressive.
The black level was hard to measure because the backlight is completely shut off when a full black pattern is displayed. By turning on a small info bug, I was able to measure 72,690.8:1 contrast, the second-best result I’ve ever recorded. With black levels this low, it’s hard to tell the difference between the top screens. Suffice it to say that a Mini LED monitor will deliver the highest contrast available from an LCD panel. To say that HDR looks amazing is an understatement.
Grayscale, EOTF and Color
In HDR mode, the color temp presets are still available, so you can calibrate if you wish. The only caveat is that the RGB settings remain the same for SDR and HDR. So, I used the same values for both modes and achieved excellent results. The brightest steps are a tad blue, but this error is almost impossible to see unless there are a lot of super-bright highlights. Nearly all HDR content will have perfectly neutral whites, grays and blacks. The EOTF takes a few slight detours from the reference line due to the action of the variable backlight. It has three modes, of which number two is the best and most balanced.
I measured HDR color against DCI-P3 and Rec.2020 and saw similar performance. DCI-mastered content will be a little over-saturated, but I doubt that will offend anyone. Rec.2020, the more commonly used standard for HDR, is also a little over-saturated until the XG321UG runs out of color just shy of the triangle perimeter. Hue targets are all in line, and saturation tracking is linear. There are no perfect HDR monitors, but this one comes darn close.