Well, the F22b version seems to be happy with a keyboard and mouse this time, so that's all good.
However, when I changed the BIOS settings to what you suggested, I also decided to bump up my Sammy Greens to 2133 by raising the multiplier. I think I had about 3 BSODs after, one even when Windows was loading. Just turned it back down to stock and it seems to be running a lot better.
So I'm guessing the problem is either my RAM (which I hope not), or my PSU being unable to cope due to age. Any ideas?
EDIT: spoke too soon, it's just BSOD'ed again