Doesn't this ignore the power pulled from the slot? Do we just assume ATX spec is being pulled from the slot?
The best test is to measure the entire system at rest and at load. That will tell you the true usage of the card. The card will consume power when idle, but since the computer isn't going to idle, it isn't a concern.
will test entire system when I get my parts for a low power MB+CPU combo and see how it affects the numbers