Monday, October 9, 2017

Do iPhones Get Slower Over Time?

Futuremark (via Wojtek Pietrusiewicz):

Our benchmarking data shows that, rather than intentionally degrading the performance of older models, Apple actually does a good job of supporting its older devices with regular updates that maintain a consistent level of performance across iOS versions.

That said, there are some factors that might affect people’s perception of performance after updating an older device with a newer version of iOS. An update might add new features that use more resources or require more processing power. New apps developed for the latest models might not run as smoothly on older devices.

I don’t think CPU and GPU benchmarks are the right way to investigate this question. Obviously, Apple is not using OS updates to slow down the chips themselves. When I see people complaining that their phone slowed down after an update, they’re often talking about a new animation that isn’t smooth. This makes the phone feel slower.

It’s possible that the new code isn’t as optimized for older phones as for new ones. It’s also possible that older phones simply aren’t capable of running the new animation at a speed that looks good. Either way, it’s fair to say that Apple has optimized the OS for newer devices, either through its allocation of engineering time or through its design choices.

New OS versions also bring new features, so there is more code running in the background and consuming memory. In summary, there’s nothing sinister going on, but I do think it’s generally true that newer iOS versions feel slower on the same hardware. In my experience, you generally don’t want to be more than two generations back. iOS 11 runs great on my iPhone SE (which has the same processor as a 2015 iPhone 6s), but I’ve heard complaints from people who have an iPhone 6 or iPhone 5s.

Mike Ash:

I raced Siri on my iPhone 6+ with iOS 11 and iPad Mini 2 with iOS 10. The iPad was waaayyyy faster despite an older CPU.

See also: comments about Mac performance changing with OS updates.

Update (2017-10-10): Riccardo Mori:

The most unfortunate device in this position is the iPad 2 running iOS 9.3.5, whose overall performance has taken a huge hit due to both these factors (poorly optimised apps, and Web advertising slowing down Web browsing). Every time I pick up my wife’s iPad 2, I keep thinking that Apple should have never allowed this device to be updated to iOS 9 in the first place.


It’s the software that, update after update, becomes more demanding and impacts performance more and more severely. Sometimes the drop is just limited to specific areas or apps. In other cases, like with the iPad 2, the snowball effect is such that the whole device becomes barely usable.

Update (2017-10-11): See also: Brian Barrett.

Update (2017-10-16): Mike Ash (podcast) reports that erasing and restoring his iPhone 6+ made it much faster.

Update (2017-11-13): Mike Ash:

Do iPhones really get slower over time, or is it just our imagination? This repository aims to keep records of iPhone performance for various models over time to objectively answer this question.

3 Comments RSS · Twitter

In many cases, it is as reported here - newer OS versions and newer apps demand more horsepower, which impacts user-visible performance.

Another issue I've noticed is that many times a device will run very slow (and hot and drain battery) for a day or two after an OS update and then go back to normal afterward. I assume this has to do with some kind of one-time system maintenance procedures (maybe re-index the Spotlight database or push a fresh backup to iCloud). Since people's first impressions are made during the first few hours after an update, that could easily give the impression that every new OS performs worse than the one before.

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