I figure out that my FPS problems just happen when I activated Instant Replay or something else like that (Instant GIF, In-Game Replay) ... When I deactivate this options I can use Radeon Software 20.4.1 and higher without any issues.
When I activate Instant Replay my FPS are dropping every 2-3 seconds while the driver tried to hook to the game (on mouse cursor u see windows loader animation). Thats annoying because I use Instant Replay frequently but cant used with Version higher than 20.4.1. on my RX590.
Also having the same issue on 20.4.1 and 20.8.1
20.3.1 was the last driver that worked for instant replay though it had some other issues for me that the next drivers fixed.
haven't tried 20.7.1
The issue is over 6 month included now...
Tested 20.9.1 - works once than never again. I tried DDU and also AMD Clean Uninstaller, without a long time solution.. Works after frech installation for once... After reboot or game restart it never worked again.
Doesnt tested 20.9.1. why it isnt listen as KNOWN ISSUE or never as FIXED ISSUE?