Can't use 170hz after gpu upgrade

Tyoma

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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?

Screen Shot 2021-12-27 at 10.54.21.png

Edit
I can use 119.88Hz but nothing above..

Screen Shot 2021-12-27 at 11.07.57.png
 
Last edited:

Shaneee

The AMD Guy
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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

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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:

Screen Shot 2022-05-25 at 12.55.32.png

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 :/
 

Tyoma

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Mar 1, 2021
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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?)
 
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