AMD's Turion 64 on the Desktop
Toasty16 writes "SPCR has an overview of using an AMD Turion 64 mobile processor in a desktop system. There's a good bit of info about motherboard compatibility and power consumption as compared to a Pentium M processor. There's also links to articles from the Techreport and LaptopLogic on the same topic. If you've been thinking about building a low power HTPC or file server, mobile processor on desktop is an interesting option."
I was running two very old machines for fileservering and routing/firewall duties. My estimate put these machines at about ~$30-40/mo to run depending on what I was doing. I was able to drop this down by about half moving to a mini ITX board with the via C3 processor, and it only cost about $150. I could have spent less, but I upgraded the power supplies as well.
You can easily measure how much power your computer draws with a multimeter from the hardware store - last time I was there I saw them for about $10. Put the meter on the AC amps scale, make sure the wires are plugged into the amp reading ports, and then wire it in series with your computer.
I guarantee you'll be suprised. I was.
..don't panic