I am not sure if the 300W HP PS could run 9800GT, but I do know my Dell 300W PS has run a 512 mb HD4670 for the past year with no issues. Not a heavily loaded system, C2D 7300, 1 SATA HD, 1 DVD-RW, 3 gb of ram. Kind of depends on what else is in the box, multiple cores CPU, 4 sticks of ram...