Help: Black screen on monitor when increasing refresh rate above 120hz?

[Arkadelic]

I recently upgraded to a dual monitor setup w/ an older LG Ultrawide (on HDMI), and a newer Gigabyte M27Q (On DP). The monitors function well together, colour is good, but I can't push the refresh rate on the M27Q above 120hz (119.88hz) without getting a black screen on the M27Q. Display settings show me options for 59.88, 119.88, 143.88, 164.75 & 169.75. When the screen goes black, I can still access the second display and revert the refresh rate to 119.88, and the picture returns.

I've confirmed the monitor can reach 170hz when I boot into windows, but not in MacOS.

What I've tried:

- Swapping DP cable (1.2 & 1.4 tested)

- Restarting/unplugging monitor / powering off monitor

- Resetting NVRAM during boot

I'm guessing this may be a graphics driver issue / maybe something in my config but unsure..


Current Build:

• i5-9600k
• MSI Z390-A pro
• G.Skill Ripjaws 1x16
• Sapphire RX 5600 XT
• WD SN 750 1TB

Running: OC 0.6.7 on Big Sur (11.2.3)

 

[Edhawk]

Can you obtain the refresh rate you require (170Hz) when just the M27Q (main screen) is connected via DP cable, i.e. the HDMI cable is not connected to your RX5600 XT?

Consider your M27Q works at 120 Hz along side the LG display at 60 Hz, this is something the AMD drivers will understand and process, i.e. double the refresh rate on the main screen compared to the '2nd' screen. Trying to get the M27Q to run at approximately 1.5 x the speed of the 2nd screen may not be something it is programmed or able to do?

As all AMD drivers are native to macOS, i.e. there are no third-party AMD drivers for macOS, I doubt this is a driver 'issue'. It may be a driver setting that is not editable in macOS.

If you want us to have a look at your Clover or OpenCore EFI folder by all means post a copy here. Just remember to delete/redact your Serial Number, SmUUID, Board Serial Number, MLB and ROM from your config.plist before you post a copy here.