I went from an Athlon XP 2200+ to a Athlon 64 3200+. Same amount of RAM, 512 meg, only now it's DDR400. Same vid card, GeForce 4 Ti4200, 128 meg DDR. My system does bog down on occassion in a big furball, but only as far as the low 30's in framerate. My next upgrade should fix that; 450 watt power supply and GeForce 6800 GT.