In the latest blog post on Engineering Windows Chris McConnel provides some tips to know whether the Search Indexer of Windows is slowing down your machine.

If you still believe that the indexer is giving you trouble, we’ve got a few things for you to try:

* Download and install Windows Search 4 (on Vista or XP).
* Download and install the Indexer Gadget from the Windows Live Gadget Gallery (Vista only). This gadget was written by one of our team members, and gives you a quick way to view the number of items indexed. It also allows you to pause indexing, or to make it run full-speed (without backing off).
* If you‘re one of those people who like to get under the hood of the car and poke around the engine, you can use the Windows Task manager and/or Resource Monitor to monitor the following processes: SearchIndexer, SearchFilterHost, SearchProtocolHost.
Engineering Windows 7 : Windows Desktop Search

UPDATE: Also see Windows 7 Search Indexer Tips.