Aww dude, wish you still had that original card, just to test a theory!
Listen folks, if you get one of these cards - any AMD card, in fact - and get serious artifact issues I recommend you do a COMPLETE removal of the drivers (manually, Driver Sweeper or whatever it's called that people recommend doesn't work anymore without purchasing it, don't waste your time) and try running version 12.8 without the CCC component installed and see what happens. Haven't tried 13.1 yet to see if they unfcuked things or not, but I will say I installed a later driver, had crazy artifact issues, got scared my card was trashed, took a deep breath, uninstalled the new stuff, reinstalled 12.8 and all was good once again.
When I had the artifacting, I did a manual removal of the drivers, and then reinstalled the ones that Sapphire had on their site. I didn't try any other versions, just the one they had listed as the latest. Is the latest driver set bugged or something?