http://www.vgmusic.com/music/console.../index-gr.html Under "Legend of Zelda, The: Link's Awakening" scroll down and click Overworld (5). This is one of them when playing back in ZQ.
When playing back that MIDI saved in the quest file, it slows down too.
When I playback this MIDI in beta 10b, it is fine. But when played back in this current build which is alpha 509, slowed down performance.