To follow up on this. I have the AMD Pro W6600 installed. Still get eye strain / pain from it. Got a clean copy of Windows 10 and the AMD driver installed last night. Turned it on tonight and I could tell right away my eyes were starting to hurt.
I was going to try the registry thing "DP_DisableDither". When I went to the place in the registry to set the key, it was already set. I'm not sure what conclusion to draw from that.
Also got Linux installed. Still got eye strain / pain while using linux (with the gnu driver).
I am going to email AMD and ask them what they think.