PC Power Consumption

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A few months ago I posted about a AC electrical power meter I'd found
advertized for $18.95.  I just purchased one, and have found it useful and
accurate.  My initial idea was to use it to check PC power consumption for
different operating modes and loads.  But what with the surge in energy
prices ...

The manufacturer is P3 ( www.p3international.com ).  I bought Model P4400
Kill A Watt.  This is a US/Canada model, 125 VAC 50/60 Hz 1875 VA Max.  The
unit is about the size of a box of kitchen matches, LCD screen and control
buttons, a three prong AC receptacle on the front and a 3 prong grounded
plug on the back.  The AC connections are standard NA, two parallel blades
for hot and neutral and a round ground pin.

Only one drawback in use.  This model has no internal battery, so you can
only read data while it is plugged in to AC power, and the data store is
lost when the unit is unplugged.  This is especially a shortcoming when you
attempt to use it in a wall receptacle a few inches above the floor.  In aid
of not crawling on my belly, I use a short extension cored B^)

Reporting capabilities:
    Power Factor
    Kilowatt Hours
    Elapsed Time.

I used the unit with my Windows Vista Home Premium / E4400 @2.7 HGZ & 1.25 v
/ 2 X 1 GByte Patriot DDR2 1066 / EVGA 680i / EVGA 8800 GT 320 MByte / Antec
Neo 550 Watt modular power supply / 2 X 500 GByte Seagate 7200 RPM SATA /
DVD R/W/RW / CD-ROM R/W/RW / Creative Fata1ity Platinum system.

I was pretty amazed at the small difference in power consumption between
idling along and heavy CPU / Graphics loads.  With no power saving features
or throttling, about 195 Watts at idle and about 225 Watts under heavy load
(monitor and other external peripherals not included, drives not heavily in
use.)  So, while waiting for Nehalem, I think I'll investigate PC power
usage.  Here in Atlanta, for the moment, my per KWH charge is about $0.08
US, so an hours computer use is about $0.016. Not much IF YOU TURN YOUR
SYSTEM OFF WHEN NOT IN USE.  But I've left my system on when not in you more
than I should have (think distribute computing projects.)  I'd always
assumed that there'd be a big difference between power consumption and high
load power consumption - but that evidently isn't always the case.

And $0.016/ hour X 24 hours X 365 = $140.00, and in my case that's without
monitor, modem, or wireless router.  And more in a year than the purchase
cost, March 2007, of my CPU!

Phil Weldon

Re: PC Power Consumption

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$0.016 you say?


Re: PC Power Consumption

'Shadow Tek' wrote:
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Phil Weldon

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Re: PC Power Consumption

I have an old Kill a Watt meter. I recently built for someone else an
nforce 6100 micro atx with a Sempron 1.8 gig which, by lottery, ran at
about 1.25 volts (they're listed at 3 different voltages, tha being the
lowest). It had 512 of ram and a WD Caviar SE 160 HD. With the Antec
Earthwatts 380 psu, it idled at only 35 watts! I loaded the 3D and cpu
up totally and it rose to 59 watts.
Ed Light

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