In the Reuse Library, the Part Copy Method option is used to determine how to create a copy on the template part.
“Use Clone Assembly” equals NX Clone (Assemblies > Cloning > Create Clone Assembly) which will create the copy right away in the native file system or the Teamcenter database.
“Use Part Rename” loads the part first and then uses NX part rename. The advantage is that the user can discard the result by not saving it. It’s faster than the other 2 methods because the saving has not already started.
“Save As” - Loads the part first and then uses the same functionality as "File > Save As" which will create a copy always as the first option.
Prior to NX 10, the part copy method used the “Use Part Rename” method. The other methods were not available in the customer defaults.