gjimmy, even if it is a old thread, it is very useful for other people. I googled for low power server and got here, so this info was useful and hope it will be more useful to other people as it is updated.
I've bought a clamp-multimeter in order to measure the power they drain. My mains voltage is 127v. Here are the results:
- Browsing the web with many open tabs (Dell Core 2 Duo @ 50% load, 2+2gb ram, medium lcd brightness): 0.3 A (38.1W)
- Idle desktop computer (Athlon XP 2500+, 1+0.5gb ram, 2 sata hd, no monitor): 1.1 A (140W)
- Full load (computing huge factorial at windows calc, heh) desktop computer (the same one): 1.5 A (190W)
- CRT monitor: 0A at standby, 0.5A powered on with medium brightness (64W)
- CRT 23" TV: 0.6 A (76W)
- 2.1 soundspeakers, 28W RMS: 0.1A at standby or medium power (13W), 0.3A at full power (38W)
I spend lots of time at the computer everyday, frequently leaving it powered on between "real world" tasks. As soon I realized I could use the notebook for most of my tasks spending 40W instead of using 200W desktop computer, I almost stopped using my desktop. This started to make me thing about making things more energy efficient.
Recently we felt the need for a home file/print server. 5 people in one house, 3 notebooks plus one destop... such a hassle keeping up where are all files. Since we already use sun heating for water and fluorescent bulbs, I don't think it would be smart to leave powered on forever a 140W PC idle most of the time just to download torrents and share files and printer across the network, so I got a NAS which is supposed to do this stuff.
Obviously, things could not be perfect. The nas itself has lots of limitations on speeds and management, and spends 10W on full load (downloading stuff) and a little less when idle. I bought a USB 500gb 3.5" HD to attach to the nas, so the HD also needs some energy to spend (accordingly to
http://extreme.outervision.com/psucalculatorlite.jsp it is 10w per sata hd or 17w per pata (ide) hd). Linear power supplies for my adsl modem, wireless router, nas, external 3.5" HD... Why not put everything being powered by a single (more efficient) switching power supply? I have lots of working AT PSUs around, so I could use one of them. Meanwhile, I've been looking for some kind of simple cheap networked media player I could plug into my network to stream music from internet and from the NAS, and found only very expensive ones. Staring at my huge collection of old PCs, I started to wonder if I could make any of them efficient enough to be powered all day long without costing me too much.
Then I wrote some guidelines:
- Leave the PC only with the essential hardware, putting away everything unnecessary that could spend energy.
- No monitor. I should control the computer using LogMeIn or other remote computing feature.
- Use some sort of hardware to allow media playback control without the need of a screen. Options are: keyboard shortcuts, IR remote control or a simple web interface I could access from my mobile (my cellphone does not have wifi, but it is able to browse the internet using bluetooth PAN if there's a computer with bluetooth around - having a always-on PC would also be good to provide bluetooth internet for the cellphone all the time). There's also a bluetooth app which enables the use of the cellphone as a mouse or a basic remote controller for media player, but it is not enough e.g. to handle playlists.
- Need usb port at least for the external 500gb drive and for bluetooth dongle. I think some of the not-too-old motherboards have two onboard usbs, I may then use a usb hub if I need more ports.
- Need some easy way to share the files with windows computers.
- Underclocking and undervolting to ensure it will spend as little energy as possible.
- Use a light OS, maybe TinyXP or DamnSmallLinux, whichever makes it easier to remotely play music, queue downloads or torrents, and demands lower power.
- As I said, older hd drives spend more energy. So, if needed, I could use a SSD to boot the OS (there are some cool CF-to-IDE adapters out there). But I've read somewhere about network boot, if it enables me to dispose of the hard disk it will be great.
- Eventually I may start using the computer for some simple automation tasks, through software and hardware (serial or parallel port) I may develop.
But I started to figure out some problems:
- Will I really be able to make the computer (processor, motherboard, ram, NIC, soundcard, hd) be energy-efficient enought to spend total of 20 or 40 watts? My NAS setup should use 10w for the HD and other 10w for the sata HD, plus some watts for the sata/usb converter.
- I have some 286, 386, pentium 75, pentium 133, pentium 166 and celeron 700. Among the ones I have, what's the processor that would suit better the requirements (low power, underclockability) and give the best performance?
- What would be the minimum RAM amount needed? The oldest pcs only take EDO pc66 memory, and I think I only have 4*16Mb of it. I have around 128 or 256mb DIMM pc100/pc133 ram. If I need more to be able to do network booting, I might find some 512mb to buy, though they're rare.
- I'm unsure about if DSL, tinyxp or other os would be more suitable for this task. Any guess?