Rumor: battery replacement makes older iPhones much faster

In a Reddit thread, many claim that their iPhone 6 or 6s has become much faster after replacing the battery. Several people claim that iOS automatically lowers the clock speed if the battery can supply less voltage, although there is no evidence for this.

Many people cite Geekbench scores in the thread on Reddit to show that the same iPhone with a new battery is indeed faster than with the old battery. In addition, many think in another app that the clock speed of their device is lower than it should be.

The theory is that with iOS 10.2.1 Apple has addressed the issue of failing batteries by letting the software determine the state of the battery and adjust the maximum clock speed of the processor accordingly. Apple has yet to comment on the theory, which so far only has support in anecdotes. MacBooks do work that way and lower the maximum clock speed as the battery wears out.

Before iOS 10.2.1 came out, many users complained about phone dropping out. That happened especially with the iPhone 6s. The anecdotes that Reddit users post in the thread are mostly about phones in the 6 and 6s series.