Tests by Redditors and professional benchmarks by Geekbench recently revealed that iPhones with old batteries were performing more slowly than they should have been. There has been a lot of speculation on the findings, but Apple remained quiet until this morning, when it released a statement to TechCrunch confirming the results.
As we speculated in our original coverage, Apple's reasoning is pretty sound: it throttles performance to extend battery life:
‘Our goal is to deliver the best experience for customers, which includes overall performance and prolonging the life of their devices. Lithium-ion batteries become less capable of supplying peak current demands when in cold conditions, have a low battery charge or as they age over time, which can result in the device unexpectedly shutting down to protect its electronic components.
‘Last year we released a feature for iPhone 6, iPhone 6s and iPhone SE to smooth out the instantaneous peaks only when needed to prevent the device from unexpectedly shutting down during these conditions. We've now extended that feature to iPhone 7 with iOS 11.2, and plan to add support for other products in the future.'
Effectively, the iPhone 6 was hitting compute peaks that the battery couldn't handle, leading to a shutdown. Apple's software update smoothed those peaks out by either capping available power or spreading requests over several cycles, as shown in the Geekbench tests.
As batteries age, they can put out less power. When the battery reaches a point where it can't provide the processor with everything it needs at a peak, Apple's code will spread out the power requests across cycles (which causes a slowdown).
TechCrunch points out that benchmarks, as artificial tests of the system, will always trigger the processor peaks and so pick up on the effect.
Apple decision makes complete sense; there was a problem with the way that the processor and battery were interacting, and the company fixed it.
On the other hand, more information from Apple about the change would have avoided this PR nightmare. If the firm had clearly stated ‘We're going to make a change that will affect your phone's performance when the battery gets old, to stop it from randomly shutting down throughout its life', it would have pre-empted complaints and kept customers (relatively) happy. Win-win.
As it was, Apple's silence on the matter allowed - almost encouraged - a revival of the ‘planned obsolescence' meme, whereas all owners actually need is a new battery.
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