DL new iTunes now editing library is taking forever

I've been cleaning up a bunch of old ugly iTunes files for the last couple months. Deleting numbers at the beginning of track names, capitalizing the first of each word, stuff like that. Usually I can fly through this stuff. After downloading the new iTunes it is literally taking Forever! If I change a single letter in the song title and hit the next arrow to go to the next track it will sit there for two minutes.

my iTunes library is large, and I keep it on a Lacie 3TB external.

HOpefully someone can help, because it's impossible to trudge through the files with it taking this long right now.