There are various "power supply calculators" available online.  Google 
should help you to find more, but here is a rather complete looking one, 
http://www.extreme.outervision.com/psucalculator.jsp .

John Sproule

-----Original Message Below-----

Date:    Fri, 27 Jul 2007 09:55:56 -0400
From:    John Pinter <[log in to unmask]>
Subject: Power Supply Capacity

I'm interested in adding an internal ZIP drive, and a required additional=
 IDE controller for it, to a tower PC.  The machine already has a (seldom=
 used) 3.5" floppy drive, an 80 GB and a 40 GB hard drive, a CD R/W drive=
, and a CD/DVD R/W drive.  The unit has a 350 Watt power supply and I'd j=
ust like to do a sanity check on whether I'd be stretching the limits of =
the supply if I add the ZIP drive and controller card.  That is, where ca=
n I get ballpark figures on how much power  the above collection of hardw=
are is using 

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