Remy,
Could you try the same test with MC's tagging turned off? (Options > General > Tagging & Importing)
We need to isolate if it's inside MC or the tagging system.
Thanks.
Ok, here goes.....
With tagging ON....
Selected my ZZ Top collection (119 tracks).
Pressed F2 to edit Artist.
Changed artist to ZY Top.
Was asked about changing 119 tracks. Said yes.
Took 42 seconds.
Still with tagging ON...
Did a "Rename files from properties" with "Artist" as one of the directory fields.
Was asked about changing 119 tracks (for "filename"). Said yes.
Took 45 seconds.
Verified that file names were actually changed.
Turned tagging OFF...
Pressed F2 to edit Artist.
Changed artist back to ZZ Top.
Was asked about changing 119 tracks. Said yes.
Took < 2 seconds.
Did a "Rename files from properties" with "Artist" as one of the directory fields.
Was asked about changing 119 tracks (for "filename"). Said yes.
Again took < 2 seconds.
Verified that the file named were actually changed.
Repeated the test with artists in other parts of the library, same result.
Question: If "filename" isn't set to write to the file tags in the first place and it's the only field changed, why does changing the tagging mode help?
Side observation: Changing tagging mode doesn't help in-place track-by-track editing of certain fields. Track Name always changes instantly, Artist and Album cause a 3-5 second pause when you hit the down arrow key (possible because auto-complete is trying to search a large library, maybe?).
Just fyi...
The volume both the music and library are on is a mirrored volume consisting of 2 Seagate 160MB Serial ATA 7200RPM drives used exlcusively for this purpose. Fragmentation low enough to be reported as 0%. Doesn't get much faster.