I have an iPad 4 on iOS 8.4.1 which I think it is OK. I just recently used my parent's iPad 3 on iOS 7.1.1, and it was blazing fast like an Air 2. It was perfectly smooth, and the whole OS was very snappy and responsive. What the hell? My iPad 4 is twice as fast as the iPad 3, but it is so slow compared to the iPad 3 now. There are stutters and lags on my iPad 4 that is really apparent now. What can I do to fix this? Will iOS 9 help?