Hi. I've got a custom-build pc with an Asus A8N-SLI mobo, A64 3500+, gig of cheap memory, 200 gigs of pata HDD (getting a Sata2 80 gig soon), 400W power supply and one EVGA 6600 GT card. I'm looking to get a second card to go SLI, but with the 7600 GT costing around $140, I'm not sure whether I should just get another 6600 GT or not anymore. Can I get some advice on the matter?