overclocking 2x 6950 in crossfire

donohue100

Honorable
Jul 9, 2012
108
0
10,680
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