You might have gotten me wrong. I updated BIOS after someone suggested it in this thread.Ok. Glad you are installing the right drivers. Two other thing I can think of right now:
1, update to BIOS 7403 (you said earlier you hadn't tried that). Some nice fixes throughout BIOS updates on your board.
2. If the BIOS update didn't help, do a fresh install with the latest drivers at the time of install.
I'm currently setting up a fresh Ubuntu installation and i'm going to try to run some games there. (i was previously on windows 10)