DupKiller 0.8.2Description by the Software Developer:
"DupKiller is one of the fastest and the most powerful tools for searching and removing duplicate or similar files on your computer. Complicated algorithms, built in its searching mechanism, perform high results — rapid file search. A lot of options allow to flexibly customizing the search.
The program will find unneeded copies of files in those locations where you even would not consider to search. There is comparison not only by name, last modification date or size. One can compare files by their contents, and what's more, to set what per cent they must match; one can search different-length files, include or exclude files by mask, etc.
In addition, unlike other programs of this sort, DupKiller performs all operations faster and better, because of complicated algorithms of data processing built in the search mechanism of the program."