radeon 9800 is the fastest available card.
nvidia fx,aka dustbuster, hasnt impressed any reviewers...
"Both cards feature support for DirectX 9 and OpenGL, as well as 8X AGP. Although both have 128MB of memory, the 5800 Ultra contains the faster 500-MHz (effectively 1-GHz) DDR-II—a misleading name, since there is no DDR2 spec yet. The 9800 Pro's 340-MHz DDR (effectively 680-MHz) works with a 256-bit memory interface. The GeForce FX uses 128-bit architecture. These differences give the 9800 Pro a memory bandwidth of 21.8 GBps, compared with only 16 GBps in the 5800 Ultra."