Ok I'll give you a quick fix for the colored screen error which happens in usually most of the rx 480-580 with old motherboards. I do not suggest or take any responsability for these fixes which has solved issues on my end. 480's bios settings are bad so flashing it to a 580 bios will do the fix.(TOP OC for strix on my end) + In your AMD radeon wattman settings there are 7 states. Set the frequency to dynamic. and set last 5 states(say from state 3 to state 7) just a little lower from your top frequency. My Max frequency is 1410. I have set mine to.
State 0 min :N/A
State 7 Max:1350
-do these at your own risk-
edit: oh and whenever in any circumstances does you radeonsettings.exe stop wroking and get a crash you will have to do the settings again. Since they will reset to the old state. You can save a wattman profile setting for ease.
I had red screens brown screens light blue screens, almost every color in the rainbow showed up on my screen on Overwatch and the fixes I described solved my issue. Even had to rma a working card because I didnt know the issue. (It was a faulty card anyway I think, because it got rma'd lol..) I dont believe this to be an issue for lets say 7th + gen intel or ryzen cpu's with a good motherboard(and ram ofc). Because that is what I lack at the moment. So underclocking the gpu kinda fixes up the bottleneck issue on the motherboard/cpu which gives a unwilling compatability between pc parts.