The new 2020 Adrenalin driver update for amd cards gave me this problem. I tried everything from changing my hdmi cable to disabling the hdmi link assurance. My monitor refresh rate kept changing from 50 hz (sometimes 24hz) when I run my games at 1080p, I have a generic monitor that has a native resolution of 1366x768 60hz but can run 1080p on 60hz. I tried using the old drivers (Adrenalin 2019 Edition 19.11.3 ) for my GPU (i have an rx 570) and voila the problem was fixed. Everything was running on 60 hz now. How can i fix this with the new drivers?