I've noticed severe drop in frame rates on a number of games with 2 of my iPhone 5s. The games most commonly affected are temple run 2 (especially nearing fire obstacle) and punch quest. The games would always start out smooth but halfway through would start stuttering and lagging very badly. And to make matters worst, once you exit the games and go to messages , the animation for imessages starts to lag and gets extremely jittery. Restarting the phone does not make the lag go away. Only a reset of system settings would. Anyone of you experienced similar problems?