is trying to use mac for auto cad a waste of time
Don’t buy this machine for these software applications. You’re better off with a high-end PC laptop or a Macbook Pro with Bootcamp.
It is technically possible to run these applications (e.g. via Bootcamp, through Parallels or Fusion or Virtualbox), but this is not their intended use.
I’m using a Macbook Pro (mid 2012) with 16 Gb RAM and a Geforce GT 650M card (not the best). I’m using it mainly for Research, but also ArchiCAD and SketchUp; alongside Office, writing, screen capturing (all native Mac versions).
It runs Revit 2015 through Parallels but it can be sluggish. For serious work, I restart in Bootcamp (running Windows 8.1 Pro natively). Be sure to add a regular mouse, as my Magic mouse is not fully usable in Bootcamp (no middle-mouse drag – which does work in Parallels using Magicprefs).