I have the iPad 4th generation, often forgotten slight upgrade on iPad 3. Both have double the memory of iPad 2, which probably explains the app refresh differe

I have the iPad 4th generation, often forgotten slight upgrade on iPad 3. Both have double the memory of iPad 2, which probably explains the app refresh difference. However, I had the iPad 1 too, and currently have iPhone 4S. Both seemed to get worse with time having been snappy to start with though. We are talking about 4-5 year old devices, possible just more OS functionality and bigger apps use up that memory.