Please post your Mac specs.
AutoCAD for Mac is 64-bit application, even initial contemporary version - 2011.
The System requirements (including hardware) for all AutoCAD versions can be found here:

http://knowledge.autodesk.com/support/autocad-for-mac/troubleshooting/caas/sfdcarticles/sfdcarticles...

Have to add that minim hardware requirements for all AutoCAD versions are the same.

Maxim