I've had my computer for a couple years and i'm looking to upgrade graphics cards without having to buy a new motherboard. Its an agp 4x only board, with a radeon 8500 aiw in it. I was wondering what the best graphics card i could is before seeing a significant drop in performance from not being agp 8x enabled. Cards i had in mind were the geforce 6600gt, radeon 9600xt or a radeon 9800 pro.