Computer freezing problem

Whenever I play Fallout 3 the game will randomly freeze, and it happens quite alot. It also does this weird stutter whenever I look up or when I turn around. My framerates drop when this happens. I have tested 2 different video cards, nothing changes, and I have also tested it with Vista 64 bit and Windows 7 64 bit, it plays the same with both operating systems.

I am not sure if this is the right section for this post, but since its a computer problem I dont know which other section to post it in.

Im thinking it has to be a hardware problem since it reacts the same with both operating systems. It also isnt a heat issue because I am monitering the temps and sometimes the game will play fine for awhile. Here are my specs:

Asus Rampage Formula X48
Intel Q9650 at 4.05 Ghz
Corsair 1066Mhz 8 gigs of ram running at 1:1 with the CPU 900Mhz
Nvidia GTX 295
WD 300 gig raptor running windows, programs and games
Seagate 750 gig with storage on it

Any help will be greatly appreciated, thanks.

I havnt run memtest yet, but I have the voltage on the ram set to 2.10v and the NB is at 1.49v and is running at 50c, and yes each ram stick has the same specs

Are those settings fine for the NB?

Well I just set it to auto and it ran at 1.6 which is way to high. So I manually set it to 1.46 just to get the temps below 50c. I dont think it will be stable in the 1.3 range. My set-up has always been weird with OC'ing. I previously had a Q9450 and I could barely get that stable at 3.2Ghz, and the northbridge was running at the same voltage as it is now. I have a feeling my particular NB doesnt like overclocking.