power consumption

if u have a 400watt power supply does that mean that your computer is using 400watts of power per hour?

0.4kilowatts/hour ?



or does the amount of power it draws from the wall vary with the needs of the computer?

Your computer uses a variable amount of power. 400W is the maximum rating, so if you go above this the manufacturer won't be held responsible for the consequences, like your house burning down.

Goop-sulator gives an approximate measure of how much juice you are using.

about 250 to 300 watts

Another thing: If a 400W PSU did always draw 400W from the wall outlet, regardless of what the computer drew, then the PSU would run a lot hotter under light loads than heavy loads, but that doesn't happen.