It might be shitty, but a good analogy is if you bought a PC with Windows 95 on it, would you expect to upgrade to Windows 98, keeping all your apps and data, then upgrade to Windows XP again with the same apps and data, and have everything work fine? You've gone 3 generations of software with the same data. Those SQLite tables (CoreData) probably need to be optimized in some way, and the easiest way to do that is start fresh and do a new sync. Or just live with your slow phone; either way I could care less.