The company says it slows down ageing iPhones to mitigate the effects of failing batteries.
Apple has confirmed that it takes measures to slow down older phones, but that it does this to offset the effect of deteriorating lithium-ion batteries.
In a statement, the company acknowledged that it reduces power demand in some iPhones, as has been reported this week by Geekbench. The reasons, Apple claims, are less to do with forcing people to upgrade than helping the device’s battery to supply peak current demands.
“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,” Apple said in a statement.
“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.”
Apple’s logic checks out. When an iPhone’s processor makes a large current demand from a device with an ageing battery, this can risk damaging components. The handset would unexpectedly shut down to protect itself, which is something 2016 iPhone users may remember as widespread problem. Last year’s update acts as a workaround by slowing down the performance of phones with older and low-charged batteries.
Apple was responding to research carried out by Geekbench, off the back of a Reddit thread that points to iPhone performance reducing as battery life dwindles. Although it's expected that battery life tends to lessen as a device gets older, due to the increased volume of recharging cycles, associated performance shouldn’t grind to a halt.
The original Reddit threat notes the performance of an iPhone 6S. Before changing the battery, the Geekbench scores were 1466 for single core and 2512 multi core. After changing the device's battery, however, these shot up to 2526 and 4456 respectively.
“From what I can tell, Apple slows down phones when their battery gets too low, so you can still have a full days charge,” wrote Reddit user TeckFire. “This also means your phone might be very slow for no discernible reason. Check your Geekbench scores and see what you get if your phone is still slow.”
Cue Geekbench. The organisation benchmarked the performance of iPhone 6 and iPhone 7 devices running on different versions of iOS to see how the kernel density changes as the operating system is updated. It discovered that the iPhone 6's score for iOS 10.2.0 appears 'unimodal' (that is, it doesn't change) in performance, but when it studied the iPhone 6 running iOS 10.2.1, the performance peaked around the average score and several other peaks around some of the lower scores. It reported that there was even more of a disparity when the iPhone 6 was tested on iOS 11.2.0.
For the iPhone 7, scores were pretty much identical across iOS 10.2.0, iOS 10.2.1, and iOS 11.1.2. However, when using iOS 11.2.0, the graph showed more peaks again, suggesting the performance is impacted the older the device becomes.
"First, it appears the problem is widespread, and will only get worse as phones (and their batteries) continue to age," Geekbench explained. "Second, the problem is due, in part, to a change in iOS. The difference between 10.2.0 and 10.2.1 is too abrupt to be just a function of battery condition."
Apple apparently rolled out an update to devices that limits performance when battery life starts to dwindle, according to Geekbench, because iPhone 6 devices in particular were shutting down unexpectedly even when the user had taken advantage of its battery replacement programme.
“Because degraded batteries last much less and end up with a lower voltage Apple’s solution was to scale down CPU performance, it doesn’t solve anything and is a bad experience… but it’s better than having your device shutdown at 40% when you need it the most,” Reddit user kadupse claims.