Keep in mind it isn't free. Modern computers can scale back the speed of their processing hardware in low demand, reducing power usage. Keeping it pegged at 100%, especially if it's run 24:7, means the electricity use may materially increase as a result.
Agree. Is there a Moustachian thread yet discussing low wattage computers? I mean, a Raspberry Pi with a small LED screen would use bugger all (the computer running off USB 2A, and of course the screen off when not in use). Home computer with the greatest number of Flops per Watt?
Internet in my part of Australia (inner city/CBD) and cloud computing with work (University) is finally getting good enough that I probably only need to run a Raspberry Pi or similar at home now, tapping into a work computer/cloud/server/supercomputer when needed to do hard processing. That means a Pi could be running 24/7 at home, when I'm not using it, on such humanitarian projects.
Be interesting to see the Flops/watt of old android smartphones as well. Running no screen or other apps, but all lined up and kept cool (dismantle case/cover etc to reduce heat load on processor?)