Fan on eVGA 7900GT causing half-second lock-ups?

[LukFilm]

OK, this is seriously driving me nuts and I *think* it might be because of my video card. But I had X850XT before and it was causing these half-second lock-ups too where sound repeats itself, mouse cannot move etc. So I'm not sure what's going on as the X850XT had a Silencer on it. I tried changing the PSUs from one 500W to another 500W but it still happens. Can anyone diagnose this? I've had integrated nVidia 6100 before and there were no problems whatsoever.

 

[acegazda]

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