Issue:
Under certain configurations, Autodesk Revit can respond unusually slow when working in a fairly complex model when running in Windows 10 hosted by Parallels as a guest OS on a macOS workstation. For example, even in an otherwise well-configured MacBook Pro such as shown below, it's possible to experience a slow response in Revit.
Causes:
The usual cause is the amount of memory (RAM) and the video settings allocated to Windows in Parallels.