Bragging rights aside, you probably won't even need all that power. There is a post recently asking if a 550W PSU will be enough for her quadcore system. And the unanimous answer was "Yes". That is a quadcore system and yet a PSU rated at less than 600W will suffice. Does a higher rated PSU uses more power, yes but only a little more compare to lesser rated PSU. Of course, this is only a result of higher excitation in the transformer or voltage divider circuit. And yes, the PSU only provides power to what was demanded by the load.