BSOD with SLi

Hi, I have a problem that happen recently to me with 2x GTX285 in SLi, crash, freeze and BSOD when i play a game like world of warcraft or starcraft 2.

I've tested the RAM with memtest86+ all night but no errors.
I've cleared CMOS and then reset BIOS to default.
Downgrade video card drivers.



Any suggestions? Sorry for my bad english

Edit: if i miss to post something important let me know, thanks