[mythtv-users] Backend hardware advice - Power usage - RESULTS

Brad Templeton brad+myth at templetons.com
Sat Aug 5 07:15:47 UTC 2006

On Fri, Aug 04, 2006 at 11:19:30PM -0700, dave johnson wrote:
> after reading your response on the laptop, i realized an oversight on my part... i hadn't waited for the flourescent backlight to shut off on the laptops.  i went back and measured them and they were each about only about 5w lower, at 20w and 29w respectively.  remember, these measurements weren't "at idle" (what would be the use ?) but "in use" and these babies are running Windows 2003 and XP respectively.  Hell, the W2k one runs at approx 20% cpu usage just doing nothing at all really (266Mhz doesn't give a lot of processing overhead for today's OSs).  although, the Tecra i don't quite get as it runs a lower cpu usage and isn't doing much.  perhaps it's just that these old laptops were always power mongers and only recently since the wave of super-efficient power manager chips became standard fare did they get efficient.   i know that my old apple 3400 lasted about an hour on a full charge while my iBook lasts about 3, and on a battery 1/2 the size.

No, actually idle is one of the more interesting power measurements if we're
actually aiming to calculate the power cost.  Most machine sit idle most of the
time and do intense work for a small portion.  Myth machines only do intense
work when playing video, recording (if they have software encoder), commercial
flagging and transcoding.   (Some people of course may be doing all these things
all day.)

Myth machines, and linux servers, tend to be on 24/7.  Because 1 watt 24/7 costs $1 or
more per year, the idle power, plus a bit more, is a good measure of cost.

Today's CPUs will burn 70 watts or more in full speed, but they all know to
step themselves down when idle.  But those older slower chips do take less

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