Chosen Solution
i recently bough a second handed iPhone 5s and the owner told me the touch is laggy and the LCD have to be replaced , i replaced the LCD with no Hope the touch is still laggy , i sent the device to a tech. Guy and he checked the phone and replaced the touch ic also with no hope the LCD still laggy. -i used to Lock and Unlock the phone to be able to use the phone for a minutes then it starts to be laggy again, -Also reinstalled iOS , nothing changed i Need an answer for this situation please. Update (10/28/2017) FIX : Okay i Have fixed the problem and it was the LCD ! i bought a non-original LCD so it caused that to happen so you need to but an original one that’s all.
My guess is the lag is a symptom of a different problem. When he locked and unlocked, it fixed the issue for a minute. That would point me towards an app that is hanging in memory. OP: Try going through and closing out apps and see if it becomes more responsive after a certain app closes. Also, try setting it up as a phone in iTunes. I’m 80% sure this is a software issue, and I would attack that first.
