Re: That's because
Altium and Solidworks both work ok under VMware Fusion on a Mac Pro, but if you are using them all of the time, a PC (win7) custom built for SW is the way to go. At my last job I had both a Mac and a PC for SW and Eagle. The PC was not allowed on the internet and stayed and clean the whole 3 years I was there. For all of my other work, I much preferred my Mac.
I had SW on VMware on the Mac so I could grab stuff from Content Central. I was laughed at for being paranoid at first, but that faded as everybody else spent far more time than I did on bug hunts.