Yes I know it for the Firefox, I think it's an issue with Catalyst 12.8 also. I had this problems with my 6950's recently this year also. Now I have a 7970.
But the problem of the hibernation troubles me and I connected it with Catalyst 12.8 drivers, because sometimes in the past Catalyst caused this kind of issues.
I don't remember which ram timings the system has. It's not mine, but I build it. So it would be better to put manually the timings?