Great article Joe.  Thanks a bunch.  Your take on extent switching was new to me.  I'm in hopes that the rest of your series will help clear up a mystery for us.

Billy, I agree with you.  This goes into our mystery.  One table with less than 100 thousand rows had sporadic inserts take MINUTES to complete.  The majority of inserts take fractions of seconds.  All DBCC indications were clean. Re-index had been done and still it happened. A specific insert would hang.  If you drop the row and re-run that specific insert would take long.

In frustration I advised the guy working the problem to drop all the indexes and recreate them.  Most are non-clustered and the clustered is PK on the identity column.  Dropping the clustered index took 20 minutes. Re-creating the indexes seems to have fixed the problem.

What the ...?