HDMI and DisplayPort discrepancy

I've noticed an issue with Mac mini M4 and HDMI vs DisplayPort. At 3008 x 1692 I can only run 120 Hz over HDMI but can run 240 Hz over DisplayPort. I have the option of 240 Hz over HDMI but it won't come out of standby properly when set to this.


Also the VRR options are different when connected by HDMI vs DisplayPort. Here's HDMI..



Here's DisplayPort...


I'm using a USB-C to DisplayPort cable and a HDMI 2.1 cable for HDMI.


Posted on Jan 25, 2025 07:51 AM

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12 replies

Jan 27, 2025 05:02 AM in response to hcsitas

Yeah that would work. I was perfectly happy running it at 3008x1692 at 120 Hz over HDMI, after all why do you need a high refresh for macOS. But I was trying to resolve sleep problems so ordered the USB-C to DisplayPort cable.


When I received it found out I could now run it at 240 Hz and had the VRR option of 48-240 Hz, but it didn't help with sleep problems. At least it wasnt a total waste of money and it also frees up a HDMI port on my monitor.


Jan 26, 2025 08:04 AM in response to nlel

If Sleep is the trigger, disabling will fix it. Sleep is unnecessary on later Macs and should be disabled. Shut for long absences/idle overnights (no downside whatsoever) and for regular operation use the settings exactly as shown below: (reboot after setting):



Also, do not manual-sleep for brief absences; use instead the Lock Screen settings to switch the display off on timer:



Once set, you can also use Control-Command-Q to immediately lock your screen (instead of waiting for the display to switch off on timer).


Lastly, keep the above settings even if no change to your problem otherwise new issues might crop up.

Jan 26, 2025 11:56 AM in response to hcsitas

No I wasn’t putting it to sleep, I was letting the monitor go into standby. With my HDMI 2.1 cable plugged into the HDMI port of the mini, it wouldn’t come out of standby when set to 240 Hz but was fine at 120 Hz, this was at 3008x1692 resolution specifically.


It would come out of standby when set to 3840x2160 at 240 Hz, my USB-C to DisplayPort comes out of standby at 3008x1692 240 Hz and also allows a VRR of 48-240 Hz whereas the HDMI 2.1 cable only allows VRR of 48-120 Hz.


I may have got a duff HDMI 2.1 cable, but it was a certified cable that checked out when I scanned the QR code at hdmi.org.

Jan 26, 2025 12:51 PM in response to hcsitas

I have no problems with my Windows 11 machine, connected to the monitors other HDMI 2.1 port, but that’s running at 3840x2160 with 150% scaling. That supports a VRR of 48-240 Hz over another HDMI 2.1 cable, the one which came with the monitor. I am running that machine with VRR switched on.


I have also enabled VRR on my Mac mini using the USB-C to DisplayPort cable. That’s set to 48-240 Hz as well.

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HDMI and DisplayPort discrepancy

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