This is true for the old Indexing Search feature for Windows Xp
The new Indexing feature in Vista is a much improved feature
It is also available for Windows Xp by a different name Windows Search 4.0
For Windows Xp users you need to download it here
You can speed uo performance by making Windows Search Index only Important & Critical Folders
Here is how to do it:
You need to add C:\Windows and C:\Program Files to the list of Index Location.
(If you have a lot of Programs installed do not index C:\Program Files as it will cause high harddisk activity.)