My iTunes is running really slow lately. When I add a new album's worth of mp3 files, it can take a minute or more to load up. When I click the library tab, I have to wait 20~30 secs for the list. I have around 20,000 mp3 files in my library (which is on a 160GB 5400RPM drive). Is there a limit to the number of files that iTunes can handle?