App Nap—or why analysis might be extra slow on Mavericks
In other words, when you start an analysis batch in beaTunes and then go on to work with other programs in the foreground, OS X may decide to essentially halt analysis, while beaTunes is not the frontmost application. It does so to preserve battery life and give you the best possible performance for the app you are working with in the foreground. While these intentions are noble, they interfere with background analysis.
But not all is lost, Mr. Redford. Finder allows you to turn App Nap off for individual applications. To do so, simply select beaTunes3 in Finder, and open the Get Info dialog (see image above). In the dialog, find the box Prevent App Nap and check it. That's it.
In beaTunes 4, I will hopefully come up with a more elegant solution.