iPhone 6s Plus lagging in games

[1BadManVan]

recently while playing any game on my 6s plus, it lags very badly, almost looks like a slideshow, then will smooth out for a few seconds and go back to lagging.

I notice no performance issues with it during normal use with anything else, I've closed all background apps and done a hard reset, makes no difference

Anyone else experience this?

 

[Aditya_S]

People are saying the lag has to do with iOS 9.3.1 which made OpenGL games perform worse. OpenGL is an API, so all games using it are affected.