[mythtv-users] recommendation for new combined frontend+backend?

Michael T. Dean mtdean at thirdcontact.com
Mon Oct 31 22:07:42 UTC 2011

On 10/31/2011 04:52 PM, Kris B. wrote:
> On Monday, October 31, 2011 8:41 PM, "Frank Hartmann" wrote:
>> In the past I did not let my system run always on, but let it manage
>> power-up and down itself by setting a bios timer. This way it runs only
>> for 2-3 hours a day. This was somewhat difficult to configure, but
>> worked quite ok for the past years.
> I have an older frontend with a normal power suppply.  In the interest
> of cutting electricity, what I ended up doing is installing powernowd to
> scale the cpu frequency (down to .35 mhz for most of the time), reducing
> consumption that way.

While this is a good idea, when I started playing around with CPU 
frequency scaling, I happened to notice that enabling CPU frequency 
scaling did very little to alter power usage with my (AMD Athlon 64 X2 
and AMD Athlon II) CPUs.  At first, I thought this was a problem--then I 
realized that the CPU at full frequency takes very little power when 
idle.  I was able to measure a very distinct increase in power usage 
with my Kill-a-Watt when I actually maxed out the processor (about 
25-40W depending on chip--where my chips are 65W TDP).  But, IME, the 
difference between the processor at full frequency while idle and the 
processor at minimum frequency while idle is about 5W, max.  Still 
worthwhile, if frequency scaling is an option, but you're likely getting 
good power savings when the processor is idle, either way.

Note that I didn't go to the trouble of attempting to measure difference 
between maxed-out-at-minimum-frequency and 
The only lesson I took from it is that idle (modern!) processors*** do 
pretty well at saving power without any specific configuration.


*** Of course, this doesn't include "toys" where Intel, for example, cut 
out all the idle-mode-power-saving capabilities to produce cheaper 
silicon that runs at the same power usage when idle or when maxed out, 
nor does it include old processors (such as AMD Athlon XP or Intel 
Pentium 3/4 era ones).

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