This is bit unclear question, but I think it's my final resort.
I've got app that utilizes UIPageViewController. It is working fine on iPhone 3GS, 4S and 5. But on iPhone 4 it is very laggy, unresponsive and animations are very slow.
This is the same build of the application, and each device is using the same iOS version (6.0.1)
Do you know anything that can cause this issue?
iPhone 4 is bit problematic when it comes to rendering, as it contains a very high resolution display with a not very good GPU. So when it comes to pushing view-heavy animations, it can slow down a lot. The 3GS is technically slower, but it only has to push a 480x320 resolution, so it is much less stressful.
I would recommend optimizing your views, setting as many of them as possible to opaque and playing with the animation options to lower the performance cost as much as possible.