Well, some time back, i got a CPU from aquamac, and it was forever stuck in a Sawtooth G4. I tried once to put it into my QS and to no avail. Finally after disassembling the Sawtooth, i put the CPU into the QS last night. Low and behold, it booted the QS without overheating and wanting to fry itself. So, my QS now has a Sonnet 1.4 GHz CPU in it and it's running OS 9 right now. I would put OS X back on it, but all the good hardware is in the PC now. Since the original 1 GHz CPU i had in it originally was not fast enough for me.