I'd wait sheo if your doing it in January with the 7xxx's on the way and with the new ram interface and pci-e 3.0 it would be wise to wait and see how the new cards stack up. To spend that kind of money with such new cards on the way it would be a shame, also i would stick away from the 590's, and instead get 2x 580's. The 590 is nothing more then 2x 570's. The 6990 is a true 6970x2 and still the fastest gpu out atm.
On topic: the 67xx's should have no issue with a 500w, and as noob pointed out it doesn't matter about the slot. You can put a 2.0/2.1 in a 1.0 slot it just won't run as fast as it would in a 2.0 slot. You'll enjoy the 6xxx's, I'm loving my 6950.
ORIGINAL: sheograth
I have a pair of 285s in SLI in my rig, going to build a new PC maybe in Jan with a pair of GTX 590s in SLI or Radeon 6990s in Crossfire, along with a 3960X 6 core 3.3ghz CPU and 16GB of RAM, going to be a monster.
