Set Full-Text Indexing Properties
Exchange can create and manage indexes for fast searches and lookups. Earlier versions of Exchange search every item in every folder, so search times increase as databases expand. With full-text indexing, every word in a database is indexed, making faster searching possible.
Indexing is a resource-intensive feature that requires considerable CPU cycles. Indexing gigabytes of data can take hours or days. Schedule indexing for times when the server is not under usage load.
You can control server performance during indexing by setting System resource usage on the Full-text Indexing tab. You limit the CPU resources that the indexing service occupies by setting server usage levels to the lower values.
To set system resource usage level: