my cpu power usage was only 327, yet can't run games smoothly.
Not following you here...your game frame rate is dependent on your GPU and CPU.
Extra wattage is not going to make any difference(well some with OC...but in general)
Like TT says, you can run any top end card on your rig with a good 550 watt.
My amd 7970 OC with and old AMD cpu (150 watt) never pulls over 350Watts.