Performance may be slow for large projects that contain many objects and data when exporting from Revit Architecture and importing into 3ds Max.
To improve performance, limit the model geometry you export. Try using a section box or hide categories of model elements that you do not need in Revit Architecture and set an appropriate level of detail level.
If the FBX Importer does not perform unit conversion, such as switching 3ds Max to Feet, the import process is much faster. See Working with large files.