Locate32 is a free tool that allows you to create custom search database files for a nominated directory (including network resources and USB storage).
You can then manually update these database files when you want to do a fast search.
It is very quick to index the files and the search results pane is very fast and functional. I have used it in the past to delete or archive Revit backup files.
Check it out at:
Locate32 Web Site – Downloads