March 17, 2007

Saving power

Until I moved to here I had not been paying for the electrical power I was using and my hut was heated by electricity anyhow so I didn't care much about the power my computer was consuming in the winter I even used my computer as a heater by running the CPU at 100% while working on the project Seventeen or Bust.

Now I have moved a place that is heated by a central heating system running on wood, I don't pay for the heat but I pay for the electricity I use so I have been trying to change a few things.

My investments in 2 P4's while living in the little hut seem a bit annoying now, I have been selling the smaller of them and now only have one system running.
I have activivated the CPU-frequency scaling in the kernel, which means that the CPU will scale down when there is no need for running at 3GHz, it is scaling down to around 400 MHz I notice a little delay in scaling up, but that is not something that annoys me to much, a bit of fine tunning of this system and I have quite a bit of power saved.
Anyhow the P4 is still eating too much power, but for the time being that is the best fix I could come up with, I don't want start investing in new hardware right now.
I think I would do well to invest in a better power supply with the 80 PLUS specification, which would allow my power supply to better follow the demand from the system instead of it being a bit conservative and eating to much power all the time, until I have that kind of power supply I don't think I will see the full effect of the frequency scaling.

Another big problem with my desktop system here is the two old CRT screens I am using for my dual screen setup, I surely would save a lot of power replacing them with two LCD's or maybe even better one big LCD (not sure about that though, I think I might get better watt/squareinch with two smaller LCD's). As I wrote earlier I don't want to make any new investments, so for now I try to remember to shut down the CRT's when I don't use them.

I am sure I will find other ways to reduce my computer power use, I will try to post about it here when I find them.


Gopher said...

Hi Arne, yeah I can see why you'd want to scale back on the P4's they do seem to EAT power no matter how you have them set up..
Have you ever considered switching to the new Dual Core version or maybe an AMD 64 dual core - I mean it's all about Watts/Ghz is it not. I know both AMD and Intel are working HARD on new lower wattage multi-cored processors but they are mainly for Data Centres.
Gopher - Team Free-DC.

Arne said...

Thank you for you suggestions and interest Gopher

Yeah I have considered exchanging this P4 with many things, but it actually seems that the CPU-scaling works decently right now without any real loss in performance and I am using a lot less power (when not running DC projects that is).

I think my main consideration was getting my hand on one of Sun's older CPU's and motherboards which I have a lot of really good things about.

Still right now with the state of my economic situation (caused by the lack of geophysics work which again is caused by this restructuring of the state authorities that usually order the geophysics jobs) this will have to wait a while, also I might start out with replacing the CRT with LCD's which would mean a nice cut in my power usage.