I currently have this: Machine speed : 400 MHz Bus speed : 100 MHz L2 cache size : 512K Machine model : iMac (version = 32.2) Boot ROM info : 4.1.9f1 and I have the chance to put in a 500mhz from another G3. Not sure the exact specs yet. Is this possible? I looked all over but kept finding info on the Sonnet upgrades and such. I don't mind reinstalling, as I want to swap harddrives anyway (10gig just ain't cutting it!).