I'm planning on buying two 6990s and the 6990s are dual gpu cards which equal quad gpus in total AKA considered as 4 cards. I had a mobo in mind but it doesn't specify if it supports quad sli / crossfire or not. The one I have in mind is the EVGA P67 FTW with 6 pci express 2.0 16x slots at 269.99 on newegg but im not sure if it will support my 2 6990s. can anyone also tell me what PSU i would need for this? I'm planning on overclocking the cards and the i7 2600k that it'll be coming with. and any tips for cooling? is the haf x case with great airflow good enough for those two cards?