Now either its a typo or nobody else saw this ultra unfair comparison. A GeForce FX 5600 compared to a Radeon 9800 pro???!!! In that case there is no contest. But if you throw the FX 5900 Ultra in the mix
its a whole different picture. Where as I would have to pick the GeForce FX 5900 Ultra Hands down. Check this article on Tomshardware and then make a desicion.
This site is my personal favorite and he lists all the current cards on the market and benchmarks them accordingly. Hope that helps you out.
ASUS A7N8X-E Deluxe
Athlon XP 2600+
GeForce FX 5700 Ultra @ 540 core/950 memory
Cooler Master Aero 4 Lite CPU Cooler
512 Corsair DDR 333 CL2 XMS
Maxtor 120 Gig 7200 w/8Mb cache
Windows XP Pro