This way you can turn off Apple's slow processor for iPhone

In late 2017, someone revealed Apple deliberately slowing the performance of iPhone phones, the company then recognizes slow down processors for power management balance between the components of the iPhone 6S, which has an outdated battery can not keep up with the speed of processors; to solve the problems of sudden stop for iPhone 6S that appeared in early 2017.


As part of the apology, Apple announced an offer to replace the iPhone battery for $ 29 instead of $ 79 until the end of 2018. Apple also promised to give free control to slow down processors to its users, which is done by iOS 11.3 is currently experimenting.

In iOS 11.3 you will find the new "Battery Health" section within the battery settings, where the user can see the "maximum capacity" which reflects the capacity of the rechargeable battery and the new phones are 100% and up to 80% after two years of normal use, "Optimize Performance" is the power management that causes slow processors, and on iPhone 6, iPhone 7, and iPhone SE phones will do automatically if the phone is unexpectedly stopped, but can be deactivated manually.

Steps
1. Go to Settings> Battery> Battery Health; Here you'll find "Maximum Capacity" and "Performance Enhancement".

2. You'll find the option to "disable" performance control under Option 2 (Optimize Performance), but this may mean your phone may experience a sudden stop if its battery is outdated especially in cold environments and when the components are overheated.

3. If the maximum battery capacity is less than 80%, then it is time to change the battery otherwise it will damage the other phone components.