Basic Testing
VESA DisplayHDR Test
The DisplayHDR™ Test Tool allows users to confirm the display parameters including brightness, color and contrast performance of high dynamic range (HDR) laptop and desktop monitors as per the set forth in VESA’s High-Performance Monitor and Display Compliance Test Specification (DisplayHDR).
Created by VESA®, the Video Electronics Standards Association, this new test tool has a simple keyboard interface that enables professional and lab-level users of off-the-shelf calibration colorimeters to test and evaluate HDR displays at the three performance levels (DisplayHDR 400, 600 and 1000) outlined in the DisplayHDR specification. See https://DisplayHDR.org

This free tool has some handy features. This screen shows what the monitor itself reports as its capabilities. We see a reported peak brightness of 1015 nits, just above what is required for the HDR1000 certification. We see a peak contrast ratio of just over 100,000:1 and the 97% DCI-P3 Color space coverage.

With HDR enabled in windows, the ROG Swift reports an effective range of 0.01 to 970 Nits.

In SDR mode, the PG27U drops down to a range of 0.38 to 76 nits.
DisplayCAL
DisplayCAL (formerly known as dispcalGUI) is a display calibration and profiling solution with a focus on accuracy and versatility (in fact, the author is of the honest opinion it may be the most accurate and versatile ICC compatible display profiling solution available anywhere). At its core, it relies on ArgyllCMS, an open source color management system, to take measurements, create calibrations and profiles, and for a variety of other advanced color related tasks.
SDR - sRGB

Starting with a Standard Dynamic Range and sRGB mode, we get an average initial brightness of 277 nits. A quick calibration gives us a DeltaE of 0.3 and reduces the brightness slightly to 255 nits.

After a required quick calibration, we get the above color space reproduction numbers, hitting a decent 72.4% coverage of DCI-P3, but this falls quite a bit short of ASUS’s specifications.


Turning on WCG mode in the OSD makes an immediate and noticeable difference in the screen, and for the better. Colors are much more robust and realistic. Let's see what change this makes.
SDR – WCG

Turning on WCG mode in the OSD makes an immediate and noticeable difference in the colors on-screen. Let's see what else changes shall we?

This shows as a radical jump in Color space reproduction. We start out at 93.2% of DCI-P3 but after a quick calibration, this jumps to a staggering 122%, far above ASUS’s specification.
HDR Mode

Turning on HDR mode lets the backlight jump to a blinding 1100 nits.

Moving to HDR gives a hit to color reproduction, back to around the sRGB range in SDR mode.
Power Usage:
Power off –25.7W (Yes, it draws more power while ‘off’ than on and in standby.)
Standby – 28.6W for a short while then dropping down to under 1W.
SDR – 71.5W
HDR – 148.8W
Bottom Light on/off difference– 1.6W
Top light on/off difference – 0.8W