BF3 wont work :(

[Combat squirrel]

Ok iv tried everything, battlefield 3 will only run for 3-4 mins before it hangs, screen goes a patterned grey.

Thought it was my overclock, gfx etc but I left it overnight on furmark for the GPU and its peak was 92c and when I got to it it was 85c.

CPU stability on LYNX for another 12 hours was fine, peak temp 61c when I got to it was 57c and still running.

So the PC seems stable, runs every other game just fine but why will BF3 not work for more than a few mins ?

PC is AMD Phenom II x6 1055t at 4ghz
16gb ram
Asus Crosshair IV 890FX
ATI 6950at6970 @ +18 on volt scale
Crucial C300 SSD, BF is installed on a samsung 1tb drive.
win7 64 bit

 

[Combat squirrel]

Interesting ill try this when I get home from work, thanks

 

[Combat squirrel]

Just thought im fairly sure as the bios is flashed to 6970, I cannot lower the memclock speed on the memory card, what software will do that ??

Also what are the default clock speeds for a 6950 and 6970 ? thanks