Re: lower power PCs

[Marc_F_Hult <MFHult@xxxxxxxxxxxxxxxxxxxxx>]

On 29 May 2008 06:42:55 GMT, ddl@danlan.*com (Dan Lanciani) wrote in message
<1348312@xxxxxxxxxxxxxxxxxxx>:

>For some time I've been using an old Dell Optiplex P3/600 for some home
>control and A/V functions.  It is a big tower with a number of PCI and
>ISA cards, three older hard drives, and a CDROM.  I was always pleased
>that it lights no LEDs on the power scale of the 1000VA UPS to which it
>is attached.
>
>I wanted a little more CPU power to allow for some MPEG transcoding so
>I'm replacing the Optiplex with a more modern P4/3GHz machine with
>two recent hard drives, a DVDR and an FX5200 video card.  (Everything
>else is on the ASUS P4C motherboard.  This "new" machine is a few years
>old, but much newer than the Dell.)
>
>I was a little disturbed that the "new" machine lit two LEDs on the
>UPS, so I got out my genuine glass-cased watt-hour meter.  Turns out
>that the old Dell draws about 60W while the new machine draws 140W.  Ok,
>I realize the "new" machine is a lot faster but I thought efficiency
>improvements had at least somewhat offset this.  Am I being unrealistic
>or should I be able to do better?

Dan,

My Server 2003 machine uses essentially the same motherboard (ASUS P4C
Deluxe) as yours with a 2.4ghz P4 CPU and five large drives. It idles at ~135
watts so your experience is probably typical.

P4's are power hogs. It was due in part the inexorable increase in power and
attendant heat that Intel to moved to dual/multi-core CPUs instead of
increasing P4 clock speeds beyond 3.8ghz. (I was fully expecting a
celebratory 4.77ghz P4.)

According to this:
http://www.tomshardware.com/reviews/intel-cpu-power-consumption,1750.html

the newest Intel Duo core CPU provide a "400% performance per watt increase"
compared to P4's.

So yes, "efficiency improvements ha[ve] at least somewhat offset" power
increases with the most recent CPUs, but not significantly with the CPUs we
use - which are close to the worst of the bunch.

Note too that some new video cards consume more than 100 watts -- even more
than the CPU in the system.

http://www.codinghorror.com/blog/archives/000662.html

You write "more cpu power to allow for MPEG transcoding" which would implies
that this is done by the CPU and not in hardware on the video card. If so,
you might cut power a bit by using a lower-power video card with negligible
loss in performance for typical HA uses. A video card that doesn't have a fan
will likely use less power than what you have.

Also: You might check to make sure that each of your disks is using minimal
power when not actually reading or writing.

Also: Check the power supply. There may be room for increased efficiency and
improvement in power factor there too,  especially if your UPS is a full time
conversion unit. The resulting five conversions each have less than 100%
efficiency:  120AC--> 160DC-->120AC-->160DC--> 12vdc+5vdc+3.3vdc.

I use a  power supply with a 24vdc input on my main HA PC and 12vdc inputs on
the smaller pcs as part of a  distributed DC power system in our home.

FWIW, the newest addition -- a homebrew, all-electric 1967 VW Beetle -- will
provide ~20 KWH of standby power at 24-hour discharge rate when charged,
parked and interconnected with home. Plans are to add solar to the roof.

See:

http://www.evalbum.com/1610

for a description of my "E-Bug".

I should also have a new web site at www.E-bug.org up Real Soon Now.

HTH ... Marc

Marc_F_Hult
www.ECONtrol.org
Visit my Home Automation and Electronics Porch Sale at
www.ECOntrol.org/porchsale.htm