Ever since I enabled iTunes Match, I feel like Music.app on my phone has become somewhat unreliable, and cumbersome at best.
When polling for the full list of artists or albums (much less songs), it sometimes takes a full 15-20 seconds of frozen, iPhone-lockup that I don't experience anywhere else. Once I give the list enough time to load, it's more or less good, albeit with noticeable stuttering while scrolling, or lag. Occasionally the whole app will appear frozen and crash. Switching between album and artist view is unfortunately an exercise in patience. This is the only thing that's slow on my otherwise fantastic 16GB iPhone 4, and if there's something I'm missing that could fix the problem I'd be glad to hear it.
Some theories I had: I'm willing to bet there are some hour-long radio shows that got tagged as "Music"-type media, and thus synced up to iTunes Match. Could a handful of long mp3s slow down the service? My library is over 100GB, is this just to be expected with an iTunes Match library of this size? I would assume that regardless of the size of the data library, the information that must be stored locally on the phone to accommodate (album lists + miniature thumbnails) must not be very much.
How could I begin to troubleshoot this?