Aye, I need some help on deciding on a new video card. I've looked at a couple cards and a few ideas, and I came down to two choices. I could also take a few suggestions. The more help, the better.
I'm running a PCI-E x16 motherboard with SLI interface, 750W Power unit, and have adequate cooling to keep the computer at an easy temperature. I plan to use if for high-end gaming and engineering programs. But I have a budget of ~$250. I also am going to run an Athlon64 X2 6400 with 4gigs of DDR2-800 if it helps.
Any card can run well on an PCI-E 16 1.1 slot with no measurable loss in performance. The bandwidth ceiling is still high enough. A gtx 260 might be your best bet because it will give you the option have sli-ing them later, but with you budget the 4870 is still the best single GPU.