It has been found recently that iPhone 5 is not as perfectly built as it seems. The problem was discovered by 9t05mac . It is a software glitch, the cause for it is yet to be ascertained. It could either be a hardware fault or a software glitch. Apparently when you scroll diagonally up and down in a repeated manner. The device lags and ultimately the screen freezes. The iPhone 5 unlike the earlier iPhone 4S is unable to keep up with the touch input.
In the video this problem is demonstrated by showing two iPhone 4S one running iOS 6 and other running iOS 6.1 and two iPhone 5 with the same configuration. And while doing the same steps as told above the problem persisted only on the iPhone 5 irrespective of the iOS versions running on them.
Check out the video to know more.