explain what is a macpicasso 520? If its a powerbook 520, You could run OSX on an Imac with the PowerBook 520 balanced on top Or if its aa LC520 or performa 520, then You could run OSX on an iMac with the 520 balanced on top. Anyway, sound like a good balancing act. Or is that one of the older clones???? so, if it's not a G3 or better, it's a big nogo. (not impossible, but not likely)