Thanks for mentioning,. SongKong can quickly identify duplicates just using existing metadata but that relies on metadata being correct so is less accurate. SongKongs main task is Fix Songs and having used this to identify albums and added fingerprints (and MusicBrainz Ids) the Delete Duplicates function should run pretty quickly. Fix Songs can take a while to run because fingerprinting is cpu intensive, matching relies on using internet to match to database and if many changes found there is I/O required to write all the changes to your files. But Fix Songs can be run completely unattended on a music collection of any size, so works well if you just let it run overnight. On a reasonable modern computer with broadband connection expect about 5000 songs to be processed an hour, for an older low powered compute or nas this may go down to 1000 songs an hour.