I recently bought an MSI R9 390 from Canada Computers in London. It has been exactly a week since my purchase.
When I first installed the card, I noticed that my Gigabyte motherboard splash screen had artifacts. I played Fallout 4 on Ultra for about an hour and then it crashed on me. Soon after, I had a friend lend me his shitty old 6850, to see if it would help identify what was going on. When I swapped out my 390 for the 6850 that day, my motherboard splash screen was visible again, and games ran (although poorly, because 6850). I swapped it back out for my 390, did a DDU and reinstalled the latest drivers (right now I have the new ones from a day or two ago). Any games using DX11 crash anywhere from 1-20 mins of gameplay. But, for example, if I swap to DX10 or DX10.1 in GTA V, I can run that on ultra, no problem. My rig should be able to handle Ultra graphics in DX11 (my 7970 ran games like The Witcher 3, GTA V without crashing).
http://imgur.com/IJbGb4p - what my post/splash-screen looks like on boot (before Windows loads...hardware issue?)
In the meantime, I have done the following:
Taken the card to Canada Computers (they ran furmark for 30 minutes and claim they saw no artifacting or crashes)
Upgraded to Windows 10 from Windows 7
Reseated the card to the other PCI-e 2.0 x16 slot and then back again
Changed slots for both of my RAM sticks
Ensured the latest version of BIOS is installed (F13B)
Reinstalled the games from HDD onto an SSD
Reinstalled dx11 through the fallout 4 folder (installer seems to be included in games that use it)
I am getting to a point where I need to do a hardware crapshoot but it is hard when I don't have much free time and everyone I know uses macs (so I can't test all my parts without paying for diagnostics at a computer store).
-MOBO: Gigabyte GA-970A-D3
-GPU: MSI R9 390 8GB
-PSU: Antec HCG-620M (based on Seasonic M12 series)
Please help if you have advice.