Here is gHacks take on Windows Search 4.0. Lifehacker too carried an article on Windows Search 4.0Martin in Windows, software Tags: desktop search, file search, locate32, microsoft, search, windows search
Microsoft released a new version of Windows Search on Windows Update and made it a recommended update for Windows XP, Windows Vista, Windows Server 2003 and 2008 users. Windows Search 4.0 introduces a wealth of new features and improvements over the previous version including the automatic indexing of shared folders, improvements in indexing online e-mail as well as in the performance and stability of the indexer.
Windows Search is basically a desktop search application much like Google’s Desktop Search. It builds an index of the files - and other information like emails - on the system after installation which takes some time depending on the size of the hard disks and the amount of files stored on them. Some users reported indexing times of several hours in previous versions of Windows Search.
It does take this long because Windows Search does not only index file names and attributes but also file contents for selected files including most text formats like Word and HTML documents but also media files like images and video formats.
I still prefer Locate32 which is resource friendly and faster in my opinion.