maybe i am wrong, i was under the impression that if you hook up a kill-a-watt meter to your device and if it indicates that the draw is 400w and if you have it hooked up to a 500w rated psu, does that not equate to a 80% load ?
No. PSUs are rated on "output", and killawatt measures "input". Converting between the 2 is about 80%-90% efficient. Therefore, if killawatt says 400w, then the output is between 320 and 360 watts, which is between 64% and 72% load.