Someone may correct me on this but. Ill give you some advice the 9600 is a AGP card i dont think they ever made a 9000 series card in PCI Express your x300 I beleive is pci express only and as far as i know they dont make pci express motherboards with AGP 8x slots in them kinda defeats the purpose of PCI Express

on a lighter note the x700 cards start at around $150 on newegg.com and that will give you a huge leap over what you have now and the 9600 if it worked is very simmilar to 128 meg x-300 in my most humble oppinion.