I am reading through civil 3D 'best practices' and found this-
Referencing a Point File
Unless you need to edit points and point groups, add a point file reference to the surface definition rather than importing the point file into the drawing. This keeps the drawing smaller and easier to process. If your surface is composed from several point files, merge them into one large point file to improve performance.
We deal with fairly large surveys that are often terribly slow, I believe we always import our point file. Can someone explain how to reference a point file? Are there any major differences or limitations in doing this?