Use the sorted_data option for create index when the data to be sorted is already in an order specified by the index key. This allows create clustered index to skip data sorting, reallocating, and rebuilding the table's data pages..
For example, if data that is bulk copied into a table is already in order by the clustered index key, creating an index with the sorted_data option creates the index without performing a sort. If the data does not need to be copied to new pages, the fillfactor is not applied. However, the use of other create index options might still require copying.
