Is there a compatibility matrix for all Mac Pro models and all versions of the OS? There is one that goes back to OS 10.8 here, but it would be nice to go back to earlier versions of the OS. I am primarily interested in compatibility on Mac Pros as they come from the factory. I'm sure that many would be interested in how to make other versions work, but it would be nice to have a matrix that designates those cases (say, with an asterisk). The earliest models aren't compatible with OS 10.8, and it is possible that there might be good reasons to run earlier versions on the OS even on later versions of the Mac Pro.