When Apple promised that even the good old iPhone 4S users were going to get the latest operating system, that is iOS 9; they rejoiced! Well it seems that the rejoices might not make them that happy after all. The latest comparison videos showing iPhone 5S, 5 and the iPhone 4S running on iOS 9.0.1, is slightly slower than iOS 8.4.1.
The videos which are posted below show boot up time and opening/closing apps and other tasks that a typical user might do. And, as you can see that the iPhone 5S/5 and the 4S do slightly lag when it comes to competing against the previous version iOS 8.4.1.
It seems the hardest hit out of all those three is the iPhone 4S, which for some users might experience a significant lag.
Although Apple released iOS 9.0.1 today, which fixes some bugs, but the improvement has not been that huge.
You can check out the video below which shows the comparison for iPhone 5S and below until 4S.