I have 2 Mac Minis, a 4,1 and a 5,3. I want to use the HD from the 5,3 in the 4,1. Since it will be doing the exact same job, it would be easier if I didn't have to copy, wipe, install anything, but before I actually get to trying this myself, can anyone suggest whether or not the OS install on a 5,3 will run on the 4,1 (assuming that version of MacOS is actually compatible with the 4,1)? I guess it mostly depends on whether a MacOS install contains all the possible drivers etc and just uses whichever is appropriate for the hardware it's running on, or, the installation is tailored to suit the exact hardware on which it is first installed and contains only the exact drivers it needs. If it's the former, HD swapping should work, but if the latter, probably not. I seem to recall back in the old days with MacOS (i.e. pre OSX) an installation was specific to the hardware, but now I have no firm idea. I will find out for myself in due course, but in the meantime it would be good to hear from others about this. Anyone done this and/or can confirm either way?