I search an alternative to Windows Search for fast indexed fulltext search in text files, source code, ebooks (pdf, fb2, djvu) and, maybe, office formats.
I don't want to use standard Windows Search, because this is a very heavy load on the system and drive.
If possible, the program must be free/gratis and portable.
What I found
I found very fast tool Everything, but it doesn't create index of file content (only names), and the author has no plans to add this functionality.
I found very good index searcher DocFetcher, but it needs Java.