That computer isn't old. I think you meant to say 1333MHz ram, but said 667 because that's what cpuz says. Have you tried the 12.11 b4 driver?
No, I haven't tried them... I'll download them now and try.
EDIT: Beta drivers didn't help. If anything, it crashes faster. D:
EDIT (Many moons later): It was because I didn't have the volts turned up. Everyone must have been busy worrying about my RAM to think about that.