I still don't get what noise you all are taking about. I have more mp3s and AAC then flac I don't here any noise. But a big problem I'm having is the stupid thing keeps getting stuck when trying to read the damn memory card i have a hour and 30 mim bus commute and had to restart it 6 times buy the time I got to my destination.
It sounds like you've got Automatic library updating enabled. Try switching to Manual library updates. The library function isn't that helpful anyway, so I'd guess most of us are going the Browse Files route. If you're just using Browse Files, there's no point in forcing the X3 to auto-update the library.
Good luck and happy listening!