Did you try the NB and SB voltages I suggested mate?
As far as my system goes I did a 6 hour stretch on WoW the other night without any issues what so ever. Vista64, 4gb OCZ, 177.39, 15.17.
I do know that before I got SLI working I would crash out no matter what game I was playing (worst I had was 5 seconds into the game, I hadn't even had time to do anything before the screen froze up).
I must admit to being tempted with the 280's but having just bought the 9800's my wife would kill me if I spent more money (well I won't be telling her about the watercooling project I am working out in my head :p)
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