anything with nforce 4 (socket 939 of course) chipset in the motherboard is the best for pci express. for agp socket 939 best motherboard is asus a8v deluxe, thats what i have. amd 64 3800, asus a8v deluxe, 6800gt agp. there are reviews saying asus a8v deluxe rev 2 is best for agp socket 939 motherboard. (dont get rev 1 they dont have agp/pci locks which are needed for overclocking very very high)