Re: NEED $2500 i7 920 gaming build upgrade.
those video cards are pci-express so they'll work on any motherboard that has that slot, like the one hefe mentioned for example.
Whether or not those cards are compatible with your watercooling setup i don't really know. I'm not sure how much gpu waterblocks cost, but you're paying a nice premium for those cards. $515 for a $400 card just for the waterblock. How much do they cost on their own?
"Is virtue a thing remote? I wish to be virtuous, and lo! Virtue is at hand." -Confucius