Hi, I'm in the process of developing a SpriteKit game. The game involves objects 'falling' from the top of the screen to the bottom, i'm using the function applyImpulse to do this. It was working fine and still is on my iPad running iOS 7.1 but for some reason the falling objects have started stuttering on their way down on my iPhone 5. Strangely the frame rate stays at 60fps throughout. I tried removing everything else from the view and just have code to generate a sprite node at random positions then apply the impulse but even like that i'm still getting the stuttering problem. Has anyone got any advice on how to fix this?