Can't use 170hz after gpu upgrade

[Tyoma]

Hey all!
I'm using Monterey 12.1 with 2 monitors:
Gigabyte m27q 170Hz and Dell P2418D 60Hz.
I was able to use the first monitor at 170hz with RX570 4GB without any problem, but yesterday I upgraded to Sapphire Pulse RX 6600 XT (with pikera boot args), and now if I choose any refresh rate above 60hz I get black screen.. any suggestions?



Edit
I can use 119.88Hz but nothing above..

 

[Shaneee]

Have you tried without WEG? I don't use it for my RX 6800 and this is what I get.

 

[Tyoma]

Have you tried without WEG? I don't use it for my RX 6800 and this is what I get.

What is WEG?

 

[Shaneee]

Shorthand for Whatevergreen.kext

 

[Tyoma]

Hi, I tried, without WEG, same result..
Tried now with my old rx570, had no issues using 170hz

 

[Shaneee]

I started using WEG again on my 6800 for DRM on Safari. I use the agdpmod=ignore flag to stop the black screen on startup. Try with that and see if it'll allow full refresh rate.

 

[Tyoma]

I started using WEG again on my 6800 for DRM on Safari. I use the agdpmod=ignore flag to stop the black screen on startup. Try with that and see if it'll allow full refresh rate.

I tried, no changes.. :/
BUT! This is strange:



I know that something is wrong with hz, because my eyes hurts after 5 minutes with this monitor.. (no problem in windows 11..)
Also, I was able to achieve 144hz with HDMI cable.. so there is some bug with DP :/

 

[Shaneee]

Check the version of your DP cable then. It may also be a lower quality cable.

 

[Tyoma]

Check the version of your DP cable then. It may also be a lower quality cable.

I'm using a good one.. This one (no issues with windows 11)
I was thinking about trying to change my SMBIOS from iMacPro1,1 to MacPro7,1.. Maybe this can help? :/
(Maybe iMac can't handle two monitors with rx6600xt?)

 

[Shaneee]

Possible. I'd copy the EFI to a USB and test out the change first there.