Apple may be deliberately slowing down older iPhones with degraded batteries to preserve battery life, a developer has learned.

After studying how some iPhone models were performing when using publicly available benchmarks, developer John Poole found that the phones' performance could vary wildly, depending on what software it was running, with many individual phones performing much worse than the "standard" benchmark established when the phone was brand new.

The lithium-ion batteries in smartphones and other devices degrade a little every time they are charged and discharged. Day to day, the degradation is negligible, but after a year or longer, users tend to notice the device no longer holds a charge as long as it used to, and particularly processor-heavy tasks (like playing graphically challenging video games) can sometimes cause a smartphone battery to discharge rapidly.

Poole founded Primate Labs, which created Geekbench, the smartphone benchmark tests that are the de facto industry standard, and his assessment looks at the iPhone 6S and iPhone 7 specifically. He found that the degraded performance with some began with iOS 10.2.1, which Apple released in January 2017 and was specifically supposed to address the problem of random shutdowns in the iPhone 6 and iPhone 6S.

Per Poole's analysis, that update apparently did not affect the iPhone 7, but iOS 11.2, released in early December, did. While the effect doesn't appear to be as widespread as with iOS 10.2.1, that could be because some iPhone 7 owners may not have updated yet, or if they have, may simply not have done as many benchmarks with Geekbench.

Poole agrees with the conclusion of the Reddit thread that inspired his study: That Apple introduced throttling for devices whose batteries have degraded, probably to prevent them from shutting down unexpectedly when the battery still shows significant capacity.

It's an understandable trade-off — random shutdowns are arguably more frustrating than just generally slow performance — though Apple appears to have been less than transparent with its customers about what that trade-off was.

Source: Mashable