Re:Calculations are a bit off (Score 1)

Definitely. Not even most high-end gaming PCs use 400 watts when idle. IMO, the author needs to take the guesswork out of his calculations and just buy a Kill-A-Watt meter: http://www.p3international.com/products/special/P4 400/P4400-CE.html They're cheap and extremely useful for calculating energy consumption and line quality (voltage/frequency).