Since long ago I had the lag in animations in my iPhone 4. A couple of days ago, the wake button stopped functioning. So before taking it to Apple I made a restore and started with a clean install. The laggy animations continued in my iPhone. So it wasn't the fault of many apps running at the same time. Today they replaced the iPhone for a new one, and this one, even with all my music, apps and info loaded, is completely lag free. My former iPhone 4 was one of the first batches I suppose. So I was wondering if the lag in animation could be the cause of faulty hardware.