i too spent a lot of time on rc5-64 and a couple of des's also.
http://stats.distributed.net/partici...id=5&id=382916
i decided not to go on with rc5-72, too much of a pain to keep the computers upto date with new clients and i wanted to cut down on my electrical bill as well. i also knocked about 15 degrees off the temp of the room with the computers shut down.