Captainrave I see you have similar system with mine. Maybe 6990 is not working with x45 chipsets. PciExpress is ver.2.0 and the card is ver.2.1. I don't know man.. Maybe it's a windows fault. SP1? In window mode only one gpu is used and it's working fine. In full screen crash. Did you reinstalled your OS? if you did, try to run the game without SP1.