I am looking for a specific forum on here (I believe it was on here) where someone had posted a bunch of settings to turn off on the iPhone to get the best performance out of iOS 9. I currently have a iPhone 6s Plus. I have done the usual and turned off Background app refresh and turned off some location settings and also have turned off spotlight search. I have been looking for a couple of days now with this specific post but was unable to find it. I forgot to save it when I had originally saw it the first time.