Normally, Mp3tag reads metadata from files when loading files, directories or playlists and stores the data in memory. Then, when you close Mp3tag, the data once read from the files is discarded and must be read again the next time you’re working with those files in Mp3tag.
This can become both time consuming and memory intensive, especially when dealing with large amounts of files. If you enable the Library in Mp3tag, metadata is first read from the files and then stored in a database that resides in Mp3tag’s configuration folder.
On subsequent reads of the file, the metadata is read directly from the database and updated if the file’s modification timestamp has been changed. In addition to that, cover art or other binary data is stored solely in the database, which can significantly reduce the amount of memory that is consumed by Mp3tag.
If you only want to keep metadata of certain directories in Mp3tag’s Library, you can configure specific directories that are included in Mp3tag’s Library. Files that reside outside of these directories are not permanently stored in Mp3tag’s Library.
Mp3tag keeps track of files if the they’re deleted or moved from inside of Mp3tag. If you delete or move files outside of Mp3tag, it’s possible that orphaned entries are kept in the database. While this is not a problem per se, you can remove those entries with this option. It checks whether the referenced files are still on your hard drive and removes the entries if it cannot access the file anymore. Just to keep things clean and tidy :)
Sometimes even enabling the Library doesn’t bring noticeable improvements, especially in loading performance.
Here are some things to consider and try:
Windows Security intercepts each of the operations performed, so if you trust Mp3tag, making sure Windows Defender doesn’t scan the library database file on each change can speed up things significantly.
Each of the changes performed also needs write operations in the Library. So the faster the drive where Mp3tag’s settings are stored, the better the overall experience. It’s a massive difference to use Mp3tag as portable installation from a slow USB thumb drive compared to Mp3tag and it’s settings (incl. the library database file) running from a fast solid-state drive.