I have a AMD 64 2800+, Asus K8V SE Deluxe, 1gyg DDR2 Ram, 7200rpm Sata1 HD's in Raid 0, Windows XP SP2.
I have the Saphirre x1950 and the game runs smoothly on high settings and 1024.
As a tip buy remove the stock fan/cooler from the card and replace it with a big one like a Zahlman or something. It is known that the stock fan is underpowered and will not cool enough.