Demigod SLI freezing

When SLI is enabled, about 15-20 minutes into a game, single or multiplayer, without fail my computer will freeze up. Like a full system lock up.  Can't move mouse, ctrlaltdel, the lcd on my keyboard locks up and my sound card is buzzing an infinite loop sound.  When I have SLI disabled, it works fine without a single problem, however I have to lower the resolution for it run over 45fps.

My specs are the following:
Core2Quad Q6600
4GB PC2-6400 OCZ ReaperX
Creative X-Fi XtremeGamer
eVGA 680i SLI
2 X eVGA 8800GTX 768MB

This problem exists in both Vista Ultimate 64-bit AND Windows 7 64-bit.

This has not been a problem with any other game I own. However, I tested my memory and hard drives anyway to see if they could be the problem but they all tested fine.
I know some games don't support SLI or Crossfire, is this one of them?
Is this a known issue and is it being worked on or will I have to drop to single card every time I want to play?  Not that it's a huge problem, but I often forget and I drop half-way through a game.

Thanks!
Greg