PC Power Management

So I have power management installed on my home PC, set to go into sleep mode if I haven't used the computer in a while. But what if I don't want it to go into sleep mode? For example, I'm downloading a bunch of large files that make take hours, or doing a backup over the network which can take all night. I could manually adjust the power settings on my computer to deactivate sleep mode, but I can guarantee you that I'll forget to reactivate it again.

There is a free software solution that I found, called Coffee. This is funny because I don't even drink coffee, but it does work for me. Coffee keeps a computer from going into power saving mode if there is network activity over a user-defined rate. So as long as the downloads keep going, so will the computer. When downloads are finished, then the computer will be, too.

Server Energy Consumption

So I have been blessed with a new computer, which begs the question, what to do with the old one? It's a decade-old Pentium 4 1.6A desktop on an Asus P4B266 motherboard that doesn't owe me anything, and is probably worth even less than that on usedottawa.com. I have wanted a home server for some time, mainly to do backup duties, for which I had been using an external drive to date. It worked fine, but it was getting a bit small and it only worked when I dragged it out of the closet. With almost 20GB of family photos among other things, we don't want to lose any of them. I set the old computer in the basement next to the freezer, connected only a power and Ethernet cable to it, and used Windows XP Remote Desktop to access it from the comfort of my desk.

Of course, the idea of a server is to have it run 24/7, but that also means paying for the resulting electricity bill. So I took that old computer and plugged in to my Kill-A-Watt meter - 96 Watts at idle! The cost to run that is about $142 a year, which is more than we pay for a whole month of electricity now. That kind of utility bill increase isn't acceptable to me, so I thought about how to reduce energy consumption. I decided to pull all of the expansion cards and disconnect power to the optical drives that I wouldn't really need with the computer in its new role. I got the power consumption down to 65 Watts.

Pretty good, but could I do better? I wondered if it would boot without a video card. The video card I had was a victim of capacitor plague. While the card's lifetime warranty was useless as the manufacturer went belly up, and although it still worked without any apparent ill affects, I didn't want to keep using it in a production environment. So I pulled the card out, and it still booted right up! Now the power consumption dropped to 46W.

Next, I set the hard disk to spin down after 20 minutes of idle. Now the idle power draw dropped to 36W.

Next I managed to get this server to go into the S3 sleep state during longer periods of inactivity, for example while we are away from home or asleep or just not using another computer on the network. That brings it down to 3W. This page offers comprehensive instructions on how to set this up, using Windows XP anyway.

Oh, in case you're wondering, the new computer, an Intel Core i5-2500, draws 52W at idle. That's quite a power saving right there over my old computer drawing 96W, especially considering it has exponentially more processing power.