New battery required
It has been rumoured for a long time, but Apple has finally confirmed that it does throttle the performance of older phones after software updates, but the reasons given very much concern power engineering – Apple uses power management technology to reduce the power draw from older batteries. In a statement to Techcrunch, the company admitted that last year’s update applied power management to the iPhone 6, 6 Plus, 6S, 6S Plus and SF. This year’s iOS 11.2 update will extend the techniques to the iPhone 7 and 7 Plus.
Apple didn’t go into too much detail about how this is accomplished, but iPhone users on Reddit and other sites have performed their own experiments to determine what they think has been happening. Users have tested the CPU speed and found that the clock speed has been slowed to reduce the power requirements of the processor. Another technique that Apple is thought to use, is to spread the peak power draw over several clock cycles to spread the strain on the battery over a period of time.
As Li-ion batteries age, their ability to supply peak power is reduced and Apple found that was leading to iPhones shutting down unexpectedly and that is the reason the company gave for applying the changes. However, there is a solution, changing the battery seems to bring the processor speed back up to full performance. Unfortunately for most people that means a trip to the Apple shop and a quite costly battery replacement.
