The Update task, also known as the indexer, is responsible for automatic
updates of both view and full text indexes. It is loaded at server start-up,
by default, and runs continuously, checking its work queue for views and
folders that require updating.
There should never be more instances of this task running than there are
CPUs for a given server.
Reduce the number of update tasks running to be less than or equal to the
number of CPUs but no less than 1.
7 Performance Tuning, Best Practices to Get the Most Out of Your Domino
Domino Configuration Tuner:
This setting is included in the DCT
catalog of best practices.