I don't even know if you would recognize a power boost if it was possible. I haven't opened my iMac and won't until I have nothing to lose, like my warranty. As for previous macs, I've taken apart iBooks, Powerbooks, and iMacs (all G3 versions) and the only one that I could remove the processor from was the Powerbook. Everything else was soldiered into the logic board, hence the reason they're called logic boards and not mother boards for Mac. With little room these computers have, I would assume it's permanent.