The SongKong 3.4 release is full of improvements to the matching process.
SongKong now does a much better job of handling multiple albums without metadata in one single folder. Previously if you had Only allow match if all tracks in album were matched enabled it had difficulty matching multiple albums contained within a single folder unless they had some existing metadata. The workaround was to disable the option but this then allowed SongKong to match partial albums, possibly not the desired outcome. Now in this release SongKong can derive metadata from the songs Acoustids and group and match the songs accordingly without having to disable the above option.
Overall SongKong is better at matching albums, before this release it would try and match a grouping completely to one album, if that failed and depending on user preferences it would then match each song one by one. Now before resorting to song by song matching it trys matches partial groups to a release. This means results are split over less albums, and it speeds up the matching process because it is quicker to match a group of songs to a release in one go rather than song by song.
There are some super larger releases in MusicBrainz and Discogs, these are usually Box Sets of the complete works of established artists. Matching songs to these larger releases can be time consuming and give the impression that SongKong has stopped working. A number of improvements have been made to prevent SongKong spending too much processing a group of songs, and a Still Alive progress bar has been added to show that SongKong is still working
Full details of all issues fixed in this release can be found