Well, one thing we definitely know that it was changed: the physical order of the records (since an index was used for eliminating dupes). It is possible that in the original table the accesses were more localized (because the table was grown 'naturally') and in the newly cleaned table accesses are scattered over a large area because the index imposed a physical ordering on the records. With a table that has millions of records every deviation from the optimum gets noticed big time. *g*