Path: utzoo!attcan!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!rutgers!mcnc!beguine!Jeff.Miller
From: Jeff.Miller@samba.acs.unc.edu (BBS Account)
Newsgroups: comp.misc
Subject: Re: Leaving computer ewquipment on all the time
Message-ID: <1084@beguine.UUCP>
Date: 17 Sep 90 05:51:07 GMT
Sender: usenet@beguine.UUCP
Lines: 33

Someone asked if PC's really do consume 200 watts: 
 
It very much depends on the machine and configuration. When
estimating power consumption it is important to note that most
switching power supplies are less than %70 efficient. 
Certain UPS schemes are also very inefficient, that must be considered
also if you are using these.

I would say the average clone draws between 100 and 250 watts. The
average monitor another 40. Power=heat, if the air coming out of your
pc carries little heat than your system draws little power, if you
notice your PC heats your room it might be drawing quite a bit. Hard
to guess, as a gentle breeze that is quite warm might carry less heat
than a strong blast which feels cooler. Measuring power consumption
for computers is complicated by the fact that the curent is drawn as a
narrow high-current pulse that tricks most AC voltmeters.
 
Equipment is generally becoming more efficient per unit processing
power. 

As mentioned, power draw is usually pretty constant regardless of
sytem load. It might be interesting to point out I had a sytem which
actually drew less power as the HD heads zipped around. Running memory
intesive programs had little impact on power consumption but programs
which used the math coprocessor did use more power.
 
I would be interested in other studies and personal experiences in the
area of reliabilty verses power cycling. I for one am a total
power-on-demand convert, it has saved me hundreds over the last
several years. I have never had a peice of equipment fail.
 
-Jeffrey
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