I want to upgrade my Dell Dimension 4700 without getting a new power supply. I saw an awsome deal at tiger direct for an xfx 8600 gt xxx for $90. I have windows vista 2gb of Ram and an intel pentium 4 3.2 GHz processor. I want to be able to run Crysis at least on medium settings at 1024 x 736 or whateve that res. is. Is this video card the best one I can get without upgrading the power supply?