hmm, I've overloaded a standard XT (80W) supply before trying to run a couple of the original 10MB hard drives (amongst other things!). Guess it depends on what cards and stuff you're running (some of those old full-length boards drew a hell of a lot of power...) I've got an old pre-XT machine somewhere with the 63W supply, I seem to remember it wouldn't even power one 10MB drive with motherboard and a single floppy drive in place... I can't remember why on earth I even tried it though, I don't think the pre-XT machines (what was their proper title btw?) would even run a hard drive... cheers Jules