How old is your Macbook? Does it have bootcamp?
The new one let you run Windows Natively so it is at full speed. You don't need to use parallels and i highly suggest you dont use it for Autocad
I had to run 3 demanding programs in my program so far, Solidworks, Catia V5 and Autocad. They all ran better on my Macbook running windows then it did on some of the school computers sadly.
As long as you have bootcamp and dual boot into Windows youll be fine