[ltp] anyone undervolting a coreduo?

[Sascha Heid]

2007/9/3, Richard Neill <rn214@hermes.cam.ac.uk>:
> Dear Sascha,
>
> You have to probably have to both undervolt and underclock to make a
> real impact. But wouldn't you be better just using cpufreq or somthing?
> [Or the dynticks stuff and powertop in the latest kernel]
> Also, is the CPU really the dominant power-consumer? The disk,
> backlight, and GPU alll use quite a lot, whereas the core-2 duos are
> pretty efficient.

Hi Richard,

I think i already did all this except underclocking below the lowest
standard clock which i dont think is possible, at least i never heard
about it.
I have about 10 wakeups/s with wlan off, 30-40 with wlan on, and
another 100 as soon as im using the pen (serial device).
Im running a full gnome-desktop (minus gnome-screensaver,
gnome-power-manager and some applets which all add wakeups).
Power-consumption is between 12W and 17W with the backlight on max
(it's not that bright of a display).
With minimum brightness i would be between something like 9W and 13W.

I heard that Pentium-M thinkpads can reach 9W with max brightness (no,
disabling one core does not help much, 0.5W at most), thats why im
jealous and a little disappointed about the (lv) core-duos.
My 1.8GHz LV Core-Duo has a TDP of 15W, a ULV 1.2GHz Core Solo is
rated at only 5.5W. I guess its not linear, but still i was hoping to
get some effects from undervolting mine. I cannot see any drop in
power-consumption though.

When i use linux-phc i drop the Voltage to the minimum for all
frequencies, 1, 1.3 and 1.8GHz.
It seems to work because on 1.8GHz that voltage apparently does not
suffice and the machine hangs instantly.

Thats why im looking for other experiences with undervolting a core-duo.

Greetings,
Sascha