the gf4 mx and titanium cards only support up to Directx 8.1 whereas the newer gf4 fx 5200-5800's support the newer Directx 9. If you don't have the money to spend on the 5600-5800's, stick with the titaniums considering that the fx 5200's are about the same speed as the mx cards since they don't have built-in fans, just heatsinks.