Whats the price difference between the two? The cheapest GTX285 i could find was 305 on newegg, which makes it quite a bit more than an ATI 4890, even the most expensive. I would suggest getting a 5870 instead, 2 if you can get your hand on them, they will use less power and perform as well or slightly better than 2 GTX285s for a bit more.
What power supply and monitor resolution will you be using because any of those setups will provide a lot of graphics power.
Get a single 5870 for $379 instead. This card OCs to very high levels. It can reach up to 1Ghz core if you are tolerant to noise. I've got it at 975 myself.
It does 19k 3dmarks by itself and 21k 3dmarks when paired with the 9600GSO as PhysX processor.
Whats the price difference between the two? The cheapest GTX285 i could find was 305 on newegg, which makes it quite a bit more than an ATI 4890, even the most expensive. I would suggest getting a 5870 instead, 2 if you can get your hand on them, they will use less power and perform as well or slightly better than 2 GTX285s for a bit more.
What power supply and monitor resolution will you be using because any of those setups will provide a lot of graphics power.