I have a PowerBook G4 with 1.5 GHz and 1.5 GB RAM running Mac OS X 10.5.8. I use Jaikoz 3.3.3. How to reproduce: Load 1400 music files. In the first 200 files set the value of the 'Album Artist' column to 'Various Artists'. Now open the Find and Replace dialog, and enter 'Various Artists' in the Find field and nothing in the Replace field. Select the Album Artists column and click on the Replace All button.
The replacements starts quickly but is getting slower and slower, after 100 replacements it takes two seconds for each file. In a real scenario after more than 300 replacements a single operation took more than 10 seconds, then I killed the process. Besides Find and Replace all other Jaikoz operations are quite fast on my machine.