iOS 16 does not kill older iPhone performance or battery life | Cult of Mac

iOS 16 does not kill older iPhone performance or battery life


iPhone 8 Wireless Charging
Don't listen to the doomsayers – tests show iOS 16 makes iPhone 8 run faster.
Photo: Ste Smith/Cult of Mac

Benchmark tests show that models as old as iPhone 8 run nearly as fast on the just-released iOS 16 as they did on iOS 15. Some devices even see a performance increase after the upgrade, while others see very moderate slips.

These tests refute the mistaken claims that iOS updates turn older iPhones into slugs. And some Apple handsets even get a considerable increase in battery life from iOS 16.

iOS 16 won’t nerf your iPhone

It’s a reoccurring refrain: “Don’t install the iOS update – it’ll ruin your iPhone.” The conspiracy theory persists, despite plenty of evidence to the contrary.

It’s possible the doomsaying won’t go away because just using an iPhone reduces the battery life over time. Daily recharge and discharge cycles inevitably wear any battery out. Some people mistakenly blame this on Apple.

As proof it doesn’t happen with iOS 16, performance comparison tests were done by YouTube channel iAppleBytes. It ran Primate Labs Geekbench 5 benchmarking app on multiple iPhone models dating back to 2017, comparing the performance of handsets with the current and previous versions of the operating system.

iPhone 11, 12 and 13 perform well on iOS 16

The iPhone 13 runs every bit as fast, scoring a 4639 on the Geekbench multi-core test when running iOS 16 versus 4627 under iOS 15. The same holds true when testing the iPhone 12. The 2020 model hit 4012 on the multi-core test running iOS 16 compared to 4030 for iOS 15 – less than half a percent difference.

Running Geekbench 5 on the iPhone 11, iOS 16 yielded a score of 3270 versus 3385 for iOS 15. That’s a 3% decrease.

The worst performer was 2018’s iPhone XR. Its multi-core score under iOS 16 came in at 2494 versus 2680 iOS 15. That’s a 7% decrease.

Before anyone gets the idea that Apple’s new operating system runs progressively worse on older models, the Geekbench multi-core score for 2017’s iPhone 8 running iOS 16 is 2394, while the iOS 15 score is 2265. That’s a 6% improvement from the new version of iOS.

Of the five models tested, two posted very similar performance between iOS 16 and iOS 15 and one experienced a speed increase. While two experienced slightly decreased benchmark scores – which are not ideal – neither drop qualifies as destroying the performance, as the warnings say.

iPhone battery life increases

Many of the more dire predictions of new iOS versions are that they’ll murder the battery life of older iPhones. To put these claims to the test, iAppleBytes tested six iPhone models – the five it already did performance tests on plus 2020’s iPhone SE 2. All of these units had replacement batteries, so their health is at 100%.

When the Geekbench 5 battery life test was performed on the iPhone 13 with iOS 16, it scored 5440. That’s 5% below the result it got for the original version of iOS 15, but better than any iOS 15.x update released in months.

On the iPhone 12, the iOS 16 battery score was 4279, much higher than any score it received when running any iOS 15 version.

And there’s great news for owners of the iPhone 11 or iPhone XR: iOS 16 gives these handsets higher Geekbench 5 battery scores than in any iAppleBytes test going back to the first iOS 14 version.

But there’s a drop for the iPhone 8. It pulls in an 1843 score – that’s 8% less. Perhaps users of this model ought to hold off upgrading until iOS 16.1 in hopes of better battery life.


Daily round-ups or a weekly refresher, straight from Cult of Mac to your inbox.

  • The Weekender

    The week's best Apple news, reviews and how-tos from Cult of Mac, every Saturday morning. Our readers say: "Thank you guys for always posting cool stuff" -- Vaughn Nevins. "Very informative" -- Kenly Xavier.