In earlier releases of SQL Server™, you could use the create clustered index...with sorted_data to skip the sort step on data that was already in sorted order. However, create clustered index always copied the data pages to a new location on the data devices.
In release 11.5, create clustered index...with sorted_data does not sort or copy data pages except when certain optional clauses are specified to create index. If these clauses are specified for partitioned tables, a parallel sort must be performed.
See Chapter 23, “Maintenance Activities and Performance,” in the Performance and Tuning Guide for more information.
