Need Sapphire 3850 help?

the specs don't indicate the wattage of the psu, but you'll probably need a new one. the 3850 requires a 450W or better psu and the card itself draws no more than 150W. the agp slot supplies less power than the pci-e slot, so an agp 3850 probably needs multiple external power connectors. I don't think there was ever an agp power connector the way there is a pci-e connector, I think you just use 4-pin molex connectors.

also, the agp version of the 3850 lacks official ati driver support and many people have had problems. but if a new computer is not possible and you are ok with the price, the 3850 is the best agp card available. since neither ati nor nvidia make agp cards any more, lots of people refer to the 3850 as the ultimate (i.e. final) agp upgrade out there. there's nothing better for agp and its unlikely there will ever be a better agp card.