[mythtv-users] Cpu and power management

Eric (MythTV) eric-mythtv at skoozdag.com
Mon Aug 4 17:52:54 UTC 2008


wouter lists wrote:
> As the energy prices keep rising, it's time to invest in a power
> efficient CPU. What CPU has the lowest power consumption? I'm gonna
> stay with Intel or AMD. High definition would be nice but is not
> required.
> 
> My local pc store told me that it's better to buy powerfull
> powersupply, eg 700Watt output. According to him it handles much
> butter the output then a cheap 400Watt powersupply. Is this correct?


Wouter:

Let me definitely suggest to you one of AMD's new 45w processors.  Dual 
core, 45w, and they produce them in 2.1, 2.3 and 2.5ghz speeds.

Also, with AMD, be sure you enable cool-n-quiet, this lets the processor 
"clock down" when its not heavily used, then immediately speeds it back 
up when extra power is needed.

The new machine I just built is based off the 2.5ghz (4850e) 45w AMD X2. 
  With cool-n-quiet enabled, it idles using a mere 44w of power.  The 
system has a single hard drive in it, 2gb of RAM, DVD drive and analog 
tuner (pvr-150).  When running a test-suite and cranking the CPU up to 
max speed with 100% cpu utilization (on both cores, so 200% total), it 
only hits 94w of total power usage.  94w total.  Amazing!

This build also uses a Seasonic "80+ Certified" PSU, rated at 350w.  I 
wish I this a kill-a-watt power meter at my disposal when I still had my 
old 65% efficient power supply in the machine.  But from reports I've 
read online, going from a 65% efficient PSU to a 80+ PSU could save you 
as much as 40 to 50w of power.  Thats a pretty big amount of savings, 
and the 80+ PSUs are coming down in price and not that much more 
expensive than their counterparts.  DEFINITELY spend the extra money on 
an 80+ certified PSU.


Good Luck...
--Eric


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