To learn about our HDR testing, see our breakdown of how we test PC monitors.
The ROG Swift PG259QN supports HDR10 signals and automatically switches over when one is detected. All picture options are grayed out except for contrast and color temp. You can choose a Kelvin value or adjust the RGB sliders, but those settings will remain in both SDR and HDR modes.
Out of our chosen sample group, only the two Asus monitors support HDR; we’ve left the others out for this comparison.
HDR Brightness and Contrast
Both Asus monitors put out well over 400 nits in HDR mode, but only the PG259QN engages its variable backlight for HDR. That fact is apparent when comparing black levels and contrast ratios. We can see the difference both in our measurements and with actual content. Though the ROG Swift PG259QN won’t be mistaken for a FALD display, it renders HDR better than most edge-lit monitors. 6,975.1:1 is quite good when compared to the rest of the HDR screens in our database.
Grayscale, EOTF and Color
When we first switched the PG259QN into HDR mode, the grayscale pattern looked quite purple. The culprit was our RGB settings for SDR mode, which had carried over into HDR mode. In order to fix this, we simply switched the color temp back to 6500K and removed any visible errors. Above the tone-map transition of 65%, there is a slight warmth that is barely visible. The luminance curve rides the spec closely with 10 and 20% levels looking a little dark. The overall effect, however, is very good.
The PG259QN will not render a larger color gamut in HDR mode; it still covers just 111% of sRGB. The impact of color is, therefore, no different between SDR and HDR. While you get a nice bump in contrast, which is noticeable, color saturation remains the same.