www.abithelp.com

Google is your friend. It is hard to say exact because different hardware has different needs- I can not remember which is stand by power and or the cmso battery its either 3 or 5 volt.

But I got this info from different sites and dell shows 1 of its systems in sleep using 1.2 watts- id guess that is pretty close for all systems->

Courtesy of doc eze

If you've not given up completely on an answer to your original question, - here's some 'ball-park' figure care of the web:

http://www.dell.com/downloads/global/co ... 620_DT.pdf
DELL Optiplex GX620 desktop claims:
1.2 Watts for Sleep mode (pretty amazing if true esp. for a desktop!)

http://www.wisegeek.com/how-much-electr ... er-use.htm
"In standby mode, a computer uses approximately 6 watts of electricity and the monitor’s electrical consumption drops to almost nothing."

http://en.wikipedia.org/wiki/Standby_power

While Windows does use some power in sleep mode, it's very small: about one-tenth as much as it would need if you left the computer running. A mobile PC typically uses 1 to 2 percent of battery power per hour in sleep mode.

http://www.triplepundit.com/2007/01/ask ... r-standby/