i have a 1.6 ghz on a 850mv mobo with rd ram & 4x agp slot with a geforce2 400mx card. i wanted to upgrade to a geforce fx5700 or ati radeon 9800 graphic card .iwanted to know if these 8x agp cards will work propely on my mobo cos i dont to upgrade my mobo? also what wud be the price of these cards?