Hi guys. Just had a bit of a play with this again and have discovered what seems like a "fix". If I set both monitors to 75hz I get the crazy flickering on any 2020 driver. However if I set my 2nd monitor to 60hz and keep my main one on 75hz NO FLICKERING at all.....!?! Not sure why that would be but it has fixed the problem for now. I can now watch fullscreen video and not a flicker to be seen. If anyone knows why this works I'd love to know! On the old drivers - say 19.1.2 I could run both at 75hz and no flickering. Something has changed in the drivers that makes it not like two ("extended") monitors running at 75hz when playing fullscreen video....?????
Now running 20.9.1 fine - just at 75hz and 60hz
Hmm I wonder if that was the real change. The other thing that changed with my setup is I'm only using one monitor at 144Hz at the moment, where I was previously using 3 at 144Hz.
Seems to be "a thing". I had no issues with one monitor at 75hz. Bad flicker with two at 75hz. No flicker with one at 75hz and one at 60hz. It's not "ideal" as on 19.1.2 I could run both at 75hz - but it's not bad as it's my secondary screen at 60hz so can't really notice any difference.
Interestingly I used to have a set up where one monitor had a max of 60hz - so that probably explains why I didn't notice the issue when it first occurred in the drivers. It's only since I've been running two at 75hz.