Power draw with E8200 and P5E-VM HDMI?

Ketan · Post by **Ketan** » Fri Mar 07, 2008 5:31 am

I recently built a file server/Myth/virtualised windows box using the components Iâ€™ve listed below. One of my criteria was to get a reasonable low power consumption. With this setup, I get 60W idle at the AC socket with both 3.5â€

mcoleg · Post by **mcoleg** » Fri Mar 07, 2008 7:24 am

does ubuntu allow for speed-step and other power-saving settings?

if it does, enable those in bios and set vcore to auto. if the cpu keeps running full speed when it suppose to idle, the configuration of the os probably needs readjusting as well.

Ketan · Post by **Ketan** » Fri Mar 07, 2008 7:39 am

Speedstep is definitely working as procinfo reports the clocked down speed when idle. I used cpuburnP6 to load the cpu and I see that it goes back to 2.66GHz. Undevolting to 1.1V makes very little difference at idle as the E8200 seems have very low power draw anyway.

I did some checking to guage the power draw of the components:
DVB card: 5W
3.5"HDDs: 2W spun down, 8W spun up (each)
E8200: total system power goes to about 82W with 2xcpuburnP6 running (100% both cores).

Without the 3.5"HDDs, DVB card and 1 stick of memory, I estimate the power draw would be about 48W. This still seems a little high?

I thought perhaps the chipset has power saving featues built in that Linux is yet to exploit due to immature drivers? I've not tried this system under Windows yet.

mcoleg · Post by **mcoleg** » Fri Mar 07, 2008 7:57 pm

setting voltage manually seems to be counterproductive with this board. it should be able to adjust vcore by itself from whatever's its max voltage on load to about 1v-ish in low-power states. for that, cpu voltage does seem to have to be on auto, however.

i can't tell you how to tweak your system in linux but i would advise you to check the bios for whatever power-saving settings there are. there're a lot of voltage options to play with.

a while ago i posted some screenies of the bios here:

http://mcoleg.blogspot.com/

in someone wants to see what i am talking about.

Magsy · Post by **Magsy** » Sat Mar 08, 2008 2:01 pm

Wow, I think that is a good result. I've been hoping I can use the E8xxx in my next server to replace an aging Pentium M and it looks like I can.

I have a low power HTPC, Aopen i945gm mobile chipset motherboard with a T5300 Core 2 Duo, 4Gb ram, a 2.5" drive and a Pico PSU. I'm using about 40w at idle and 75w under hard load (gpu loaded too). This is with the CPU undervolted as far as possible.

Considering you have a desktop chip and chipset, I think it is good.

fri2219 · Post by **fri2219** » Sat Mar 08, 2008 2:42 pm

mcoleg wrote:can't tell you how to tweak your system in linux but i would advise you to check the bios for whatever power-saving settings there are. there're a lot of voltage options to play with.
.

If anyone is interested in tweaking their system in Linux, cpufreq-set lets you set power profiles from the CLI, while the KDE Power Manager Applet or the gkrellm2 plugin work from a GUI. AFAIK, there's nothing out there that tweaks voltages and multipliers like the utilities available for windows.

That said, cpufreq works pretty well for keeping heat and power draw down.

jaganath · Post by **jaganath** » Sat Mar 08, 2008 3:05 pm

I have a low power HTPC, Aopen i945gm mobile chipset motherboard with a T5300 Core 2 Duo, 4Gb ram, a 2.5" drive and a Pico PSU. I'm using about 40w at idle and 75w under hard load (gpu loaded too). This is with the CPU undervolted as far as possible.

those figures seem quite high for what is basically a laptop put into a desktop. what kind of power meter are you using?

fri2219 · Post by **fri2219** » Sun Mar 23, 2008 2:15 pm

Wouldn't it be great if deleting posts was supported?