[mythtv-users] silent and low-power: AMD or Intel?

[Alex Butcher]

On Fri, 5 Jun 2009, John Drescher wrote:

>> AFAIK and it was discussed on this list, frequency scaling on Intel is
>> only useful to limit a processor from over-heating and will not change
>> the power consumption significantly, if at all
>
> I have just tested and verified this on with a brand new core2 quad
> 9650 3.0GHz here at work.

My observations conflict with this statement.

I have a Core2 Quad Q6600 also on an Asus P5Q board. It has 4GB of memory, 2
1TB SATA HDDs, 2 200GB PATA HDDS, a Promise PATA card, a Hauppauge Nova-T
DVB card, a Lite-On DVD-Rom drive and a Sony Optiarc writer. At idle on a
GNOME desktop, my no-name power meter shows the system drawing about
107-116W. The system runs FC10, and uses the ondemand governor module
(acpi-cpufreq) in the 2.6.27.24-170.2.68.fc10.x86_64 kernel.

I started up four terminal windows and in each ran:

 	while [ true ]; do true; done

Each instance causes one core to jump from 1.6GHz to 2.4GHz. I then killed
them off one by one and recorded the power consumption.

Instances	Power
4		174W
3		154W
2		138W
1		127W
0		116W

The TDP of the Q6600 is 105W. (105W/2400MHz)*1600MHz=70W, so the power
savings are better than one would expect from a simple frequency comparison.
Intel's TDP definition is a typical, rather than maximum power consumption,
so this is also a contributory factor.

> John

Best Regards,
Alex