Mac Mini M4 and HDR with QHD (1440p) scaling and 120+Hz?

[reagle]

I'm using the Mac Mini M2 Pro (binned) with the INNOCN M27V2 monitor. I thought I'd be able to have HDR with QHD (1440p) and 120+Hz, but can't.

• HDMI 2.1 (included cable and a certified Monoprice cable)

  • 3840 x 2160 120/140Hz
  • 2560 x 1440 60Hz (preferred scaling, but HDR only at 60Hz)
  • 2048 x 1152 144Hz
  • 2304 x 1296 120Hz

• USB-C DisplayPort alt mode (included cable)

  • 3840 x 2160 120Hz
  • 2560 x 1440 60Hz (preferred scaling, but HDR only at 60Hz)
  • 2304 x 1296 120Hz

I purchased BD and hoped that if enabled flexible scaling, I could select the working combo of "HDR 3840 x 2160 140Hz" and then scale the GUI to my preferred 1440p screen, but that didn't work. I'm new to all of this, so any suggestions are welcome.

[waydabber]

Hmm. Now are you using M2 Pro or M4 (as in the title)?

But indeed, HDR refresh rates are limited for some reason. The limitation is based on refresh rate and scaled (framebuffer) resolution, so it depends on the framebuffer pixel clock, not on the output resolution/timing. For 120Hz you should have HDR working at 2304x1296 though (or even a bit higher with flexible scaling, but below 2560x1440).