I'd like to upgrade the Core 2 Duo 3.06 CPU of my iMac 10,1 21.5". I already done the same operation in a white Core Duo iMac, being able to install the unsupported OS X 10.7. I'd like to do the same on the 10,1 but what CPU can I install? It seems that the i3, i5 or i7 are phisically different, am I right? And the user Tim report in being unable to make it work with a Core 2 Quad. So... what are the possibilities? Thanks!