overclocking 2x 6950 in crossfire

[donohue100]

Hello. I want to overclock one or both my GPU but it crashes out. I am using CCC. Its not a temp problem. First card is 6950 @830 mhz - memory 1300 the second is 6950 @ 800 - memory 1250. these are stock values, whole thing freezes when I try and run a game and I have to reset. No crash log is made. Which card would be the best as the primary card? Any help would be much appreciated.

Windows 7 64
8 gig ram
amd phenom II 965
M5A97 PRO

 

[Cons29]

2 6950 not enough? anyway, what is the temp? (although you said its not a temp issue)

also, it might be the psu. or maybe it just doesnt oc well

 

[donohue100]

first card temp is 70 second is 50, on full loads, idle at 30, power supply is 750 I think.

 

[Cons29]

take it slow, till it goes haywire again

 

[donohue100]

Fix - disable ULPS