HDR works at 60Hz but disappears at 100Hz / 240Hz on ASUS PA32UCDM (Mac mini M4 Pro, BetterDisplay)

[iamcolak]

Hi everyone,

I’m using an ASUS PA32UCDM monitor with a Mac mini M4 Pro, and I’m trying to use it at 3008×1692 resolution with 240Hz and HDR enabled using BetterDisplay.

At the moment, HDR works perfectly at 3008×1692 when set to 60Hz, but as soon as I switch to 100Hz or 240Hz, HDR completely disappears. This happens both over USB-C / Thunderbolt and HDMI, so it doesn’t seem to be a cable issue.

I’ve already tried creating custom HiDPI resolutions in BetterDisplay, using EDID override, and confirming that the native panel resolution remains 3840×2160. Despite this, HDR only works at 60Hz and not at higher refresh rates.

What I want is to use 3008×1692 at 240Hz with HDR enabled, but I can’t seem to make it work.

Is this a limitation of macOS, or is there a workaround using BetterDisplay, EDID overrides, or custom timings?

Any help or insight would be greatly appreciated.
Thanks in advance!

[waydabber]

Yes, this is a framebuffer pixel clock limitation in macOS.

More info and some workaround that works for some configs: #3406

[waydabber]

Also: https://forums.macrumors.com/threads/dp-usb-c-thunderbolt-to-hdmi-2-1-4k-120hz-rgb4-4-4-10b-hdr-with-apple-silicon-m1-m4-now-possible.2381664/post-34342395