I haven't looked at "howstuffworks" yet, but ...
My Athlon is running with three hard disks and
a 250 W power supply.  The CPU fan sounds like
a leaf blower, 24x7.  I wonder what all that draws?

George Toft wrote:

> http://www.howstuffworks.com/power-supply3.htm
> says a 300 Mhz Celeron Motherboard consumes 18 watts, and
> a PCI card takes 5 watts, so that means your dual NIC
> firewall will consume under 30 watts, or $1.94/month.