Typical Audio Books I used it with were about 100 files… IIRC the kill notifications sometimes appeared much sooner, even without something nasty as alien dalvik or browser running.
To be fair, I really didn't know how to read the file info, so I just loaded the files in a QML-Audio-Component one after another. Not the best Idea, but the only one I had before not caring anymore. But even listing of folders took too long for my taste.