How much do Apple slow iPhones down?

Joe McCormick investigates one of the biggest controversies in Apple’s history.

Apple are the pioneers of the smartphone world. When the iPhone was first announced in 2007, the keynote’s audience laughed at Steve Jobs when he said that the primary method of controlling the device was with touch controls. Technology was well and truly in the generation of plastic keyboards and tiny screens – and Apple was the breath of fresh air in the industry.

It has now been over 14 years since Jobs made this announcement, and in that time, the technology packed into the devices we put in our pockets has jumped in leaps and bounds. We now have OLED displays and cameras that record 4K footage at 60 frames per second at the tap of a button. We can connect with people all around the world, track other devices we own with services such as FindMy and even incorporate digital objects into the world with Augmented Reality. And the cherry on top of this is that devices are getting so much faster. Everything we need to do can be done in seconds thanks to the incredible processing power of the latest chips that are being upgraded year after year.

Performance in smartphones is getting better than ever. Or is it?

I was casually using my iPhone 11 one afternoon when I started to notice that it wasn’t as ‘snappy’ as it once was. Apps would take longer to launch, the frame rate of some applications started to drop and it just wasn’t as good as I remember it being.

Released in late 2019, the iPhone 11 is by all means not an old phone. It didn’t take long for me to think back to the poor iPhone 6 I was using two years ago that was truly reaching the end of its life. That device started to become unbearable to use – apps would crash, the frame rate was slow and buggy, the battery would drain in just two hours of use and it wasn’t able to support the newer, more secure iOS updates. Switching from the iPhone 6 to the iPhone 11 was like trading in a rusty old car from 2003 with 120,000 miles on the clock for a brand new Lamborghini Huracán, I couldn’t believe how much better the performance was.

But, two years later, I find myself wondering what happened to that performance, and after a bit of research, it turns out batteries are responsible for this drop in speed.

Batteries are to blame

On 19th November 2020, the BBC published a news article explaining why Apple were set to pay $113 million (£85 million) in order to settle allegations from a scandal known as ‘BatteryGate’ – an outrage at the technology giant caused when they started intentionally slowing down their iPhone devices without disclosing the reason why. Since this lawsuit, Apple have added pages to their website that explains why batteries are the cause of the drops in performance.

“All rechargeable batteries are consumables and have a limited lifespan,” claim Apple, “eventually their capacity and performance decline such that they need to be replaced.”

Much like the disposable batteries you can purchase at a supermarket, rechargeable batteries also have the ability degrade to the point of no longer working. This has a knock-on effect on the rest of the device’s performance, as a degraded battery will start to make the device unusable.

The Apple website claims that “in order for a phone to function properly, the electronics must be able to draw upon instantaneous power from the battery.” This is a process that becomes a lot more difficult when the battery is outputting less power as a result of degradation.

What does this have to do with my iPhone’s performance?

Every year, Apple releases a new version of their operating system, iOS. While this operating system is optimised for the devices that support it, there is no doubt that the newer devices in Apple’s line up will have a much better user experience, and this is a result of the evolution of software.

Over time, apps and games have started to become a lot more intensive. Games such as Minecraft Pocket Edition, which started out as a game with limited world sizes and a couple of hundred items, have since updated to include infinitely generated landscapes, hundreds of items, servers to connect to and other texture packs to alter the game’s appearance. While devices such as the iPhone 6s were able to handle the previous iterations of the game with ease, the newer versions are becoming a lot more tricky to run.

This is due to hardware limitations. As apps get updated, they can become more intensive on the hardware they run on. For example, software may require more RAM than it once needed, it may require more work from the processor and graphical processor; but as the battery starts to wear, it becomes harder to get a lot of life out of the phone. When these batteries degrade to the point of not being able to provide enough power, user experience will start to become a problem.

The iPhone 6s, which has a processor called the ‘A9’, is currently the oldest iPhone supported by Apple’s latest update – iOS 15. When compared to the ‘A15 Bionic’ chip that is inside the iPhone 13, the iPhone 6s starts to look a bit sad and will struggle with more intensive programs.

How do Apple slow down their devices?

In order to give the users a better experience, Apple throttle the applications that are too intensive on the components in order to improve the battery life of the devices. According to their website, “with a low battery state of charge, a higher chemical age, or colder temperatures, users are more likely to experience unexpected shutdowns. In extreme cases, shutdowns can occur more frequently, thereby rendering the device unreliable or unusable. iOS dynamically manages performance peaks to prevent the device from unexpectedly shutting down so that the iPhone can still be used.” In order to do this, Apple will lower the frame rate of some applications and while scrolling; as well as make apps take longer to launch, make the speakers quieter, changing how applications are open in the background and even deactivating the flash in ‘extreme cases’.

The company claims that in order to do this, they look at “a combination of the device temperature, battery state of charge, and battery impedance” and will “dynamically manage the maximum performance of some system components, such as the CPU and GPU, in order to prevent unexpected shutdowns,” but only if the previous combination of variables require the management to be made. While this isn’t a concern for users that have purchased iPhones recently, as your device gets older, the battery’s maximum capacity will start to drop and thus start implementing this dynamic management feature.

According to Apple, the dynamic management feature is programmed differently for different devices, which are outlined below:

  • iPhone 6, iPhone 6 Plus, iPhone 6s, iPhone 6s Plus, iPhone 7 and iPhone 7 Plus all use software within iOS (starting from version 11.3) that “dynamically manages performance peaks to prevent the device from unexpectedly shutting down so that the iPhone can still be used.”
  • The iPhone 8, iPhone 8 Plus and iPhone X started using the dynamic performance management feature as of iOS 12.1.
  • The iPhone XS, iPhone XS Max and iPhone XR started using the dynamic performance management feature as of iOS 13.1.
  • The iPhone 11, iPhone 11 Pro, iPhone 11 Pro Max and any iPhone beyond this generation have the dynamic performance management feature built-in to their software out of the box.

The technology company states that for any device before the iPhone 11, the dynamic management feature is activated after the first unexpected shutdown, and users are able to deactivate it in the Settings app, however, it will re-enable every time an unexpected shutdown occurs.

The concept of slowing a phone down, at the time of when ‘BatteryGate’ was trending, did not sit right with users of the iPhone. Many believed that Apple were simply making an excuse after attempting to trick customers into upgrading their phones on the basis that their existing phone was getting slower and eventually unusable.

A battery degradation investigation

Since we know that Apple do, in fact, slow iPhones down, the next question that came to mind was ‘how much do they actually slow these devices down?’ A quick Google search doesn’t come up with any notable results as to how much performance you can expect to lose, so I took matters into my own hands. I decided to investigate.

To start off my investigation, I decided to run a poll that allowed iPhone users to anonymously submit information about their devices, as well as share their opinion on the scandal. I also got my hands on four iPhone 11 devices to conduct tests on and to try and find evidence of the devices being slowed down by different amounts. Finally, I took a look at some speed tests run by YouTubers at the time the phone was first released, and compared my data to them in order to form a conclusion.

I opted to use the iPhone 11 for my test as I believe it was in the sweet spot of being a relatively recent phone, but old enough to show drops in performance.

What did I find?

Testing iPhones to compare speeds is a much more difficult task than meets the eye due to the number of variables that are present when performing the checks. For instance, iPhones that are on different versions of iOS may yield different results, internet connection and Bluetooth connection may also be a factor, as well as how many apps are open in the background of the tests.

In order to make the results as fair as possible, I used four iPhones that were all on iOS 15.1, the latest version at the date of testing. The iPhones were all disconnected from mobile data, and only had Wi-Fi and Bluetooth turned on in Control Centre – though no Bluetooth devices were connected. Every test would have the app drawer cleared at the start, and the devices would be filmed and analysed frame-by-frame for precise launch times.

The four devices I used all had different ‘maximum capacity’ ratings – a figure that tells you how much life is left in the battery, with 100% being a brand new battery and 80% being the point where you should consider a replacement. My personal iPhone was one of the four in the test, and had a battery health of 84% at the time of testing. Two of the iPhones had 88% battery health, with them interestingly having a 13-month age gap between the date of purchase; and the final phone was on 96% maximum capacity after being bought in January of 2021.

I conducted boot-up tests for the device, camera launch tests, the launch of native iOS apps (such as ‘Settings’ and ‘Phone’), a Snapchat launch test, a Pokemon GO launch test and also a Geekbench test to compare processor core scores.

The results I found were those that I expected, though the extent the devices were slowed down by were what I was surprised by the most. The iPhone 11 with 84% battery health took 23.33 seconds to boot up from the frame the Apple logo becomes present to the frame it disappears, while the iPhone 11 with 96%  only took 18.50 seconds. This means the 11-month-old iPhone can boot up 20.8% faster than the 24-month-old device. Interestingly, the two smartphones with a maximum capacity of 88% had relatively similar times of 19.375 seconds and 19.958 seconds, with the older device actually being the faster of the two.

When it came to the native iOS app launch tests, the difference in load times was not massive, but still to the point where I believe it is noticeable. On first load ups, the front-facing camera would launch around 0.2 seconds slower for the 84% device than that of all three of the others – a margin that is quite surprising for a device that is two years old, and not even the oldest of the four devices. Snapchat would see very similar launch times to the standard camera tests.

The settings and phone app launch tests saw barely any difference between the three phones as the apps are not considered to be intensive on the device. Launching a camera takes more effort from the processor as it has to activate and render the output of the camera, thus causing longer delays from the older phones.

The Pokemon GO test yielded interesting results as I chose an app that – like the boot-up test – has a long start-up time. The only variable that interferes with this test is the internet connection – with the 84% and one of the 88% iPhones being on one Wi-Fi network, and the remaining two being on a different network at a different location. Interestingly, even with a connection that is around 30mbps faster than the other, the 84% battery health iPhone was still much slower than the younger devices with a launch time of 11.66 seconds. The device with 96% battery health, surprisingly, was the second fastest with a time of 8.85 seconds, with one of the two 88% devices loading in just 7.70 seconds. This result surprised me the most as these two devices were on the same Wi-Fi network, though I believe fluctuations in the connection caused the faster load time. The other 88% iPhone took 19.33 seconds to load, which I believe is an anomalous result.

Finally, I used an app called GeekBench to look at the benchmarks between the four devices. GeekBench conducts tests on elements of a processor by simulating processes that may be used by programs in order to produce Single-Core and Multi-Core scores.

In terms of the Single-Core score, there was only a difference of seven points in GeekBench’s rating over all four of the phones, however, the drop is a lot more considerable in the Multi-Core score. The 84% capacity iPhone 11 had the lowest Multi-Core of 3,386 while the 96% device had the highest of 3,512. The 88% devices had barely any difference with scores of 3,497 and 3,495. This data suggests that the younger iPhone is much more powerful than the older iPhone when it is using applications that require multiple cores from the processor.

I also asked users in my survey to describe their experiences with their personal devices. Around 48% of users described their phones to have dropped in performance since they started using them, though the majority of these users reported their phones to only be a ‘bit slower’. The average battery health from all the figures in my survey was 91% and the most common phones were the iPhone 11 and iPhone XR, with 29% and 14% of the total results respectively.

What can be taken away from this?

The tests I conducted show the extent of which iPhones are slowed down as a result of battery deterioration, but whether this is ‘right’ or not is a different question. As a consumer of a phone, I cannot say that I am happy that after almost two years of use, my phone is running much slower than it used to. While launching apps such as the settings and phone app barely drop in performance, the fact that the more intensive apps drop in frame rate and speed by a considerable amount is quite frustrating – especially for a phone that once cost over £700.

The data from my survey backed up my thought process, with just over 39% of responses thinking that intentionally slowing down a device in order to improve battery life is an ‘awful idea’. 47% (the majority) of responses, however, claimed that they ‘don’t really care’ that Apple slow down their devices, and only 12% of people thought it was a good idea.

The survey showed a lot of users state that they prioritise performance over battery life, while other people believe that performance should be good regardless of the state of the battery. One user said “I think it’s dishonest. It prompts people to think the phone is out of date or failing. I would rather spend on a new battery than fork out hundreds of pounds on a whole new phone. This phone suits me. Why should I be forced to change?” while another user said that “the phones should be able to last and not have their performance affected. They are too expensive to not work very well.”

On the other side of the fence, some users defended the practice, with one user saying “[I] Would rather have the battery last longer and my phone be a bit slower than a phone that’s speedy but dies very quickly.” Another user commented “I’d rather my phone continue to function but with degraded performance than shut down randomly because the battery can’t deliver enough power. I would prefer if they showed a notification or some clear indication that this is the cause though, rather than letting people think “oh my phone is getting slower because it’s old – I have to upgrade my phone for it to get faster again”. A battery replacement has completely changed my experience with my phone.”

What do Apple have to say?

After conducting my tests, I decided to go into the Apple Store and ask if my battery, despite the drop in performance, was covered by my AppleCare+ plan to see if a new battery can be fitted. The technician ran a couple of tests and deemed the battery to be in a good enough condition that the warranty wouldn’t cover a replacement as it passed the battery checks and the battery health was not below 80%.

When I asked if they knew how much I can expect my phone to slow down, the technician was unable to comment, which leads me to believe that the amount a device slows down is specific to your phone and suggests that the employees are not trained to understand how the software throttling works. The technician did, however, recommend reinstalling any apps that struggle with performance and also turning the ‘background app refresh’ setting off in the device preferences. The Apple press office failed to respond to my enquiry.

Final thoughts

The results of my investigation saw a very linear drop in performance as the health of the battery goes down, but just how low it gets was the factor that surprised me the most (and I can imagine the experience with older phones is even worse). Overall, I believe Apple in their statement that the performance drops are a measure to protect the batteries and this is not a case of planned obsolescence; however, I will continue to stand that it is unacceptable for a two year-old phone to become as slow as it is. While a lot of people seem to be unbothered by this drop in performance, there are still a lot of people that, like me, believe this is a bad business practice.

With iPhones constantly being released every year; and the 15th anniversary of Apple’s hit phone being just around the corner, I sincerely hope my favourite technology brand can find a balance between performance and battery life. Because, quite frankly, having a device’s performance throttle as much as it has in such a short period of time is unacceptable. Come on Apple, you can do better.

Joe McCormick


[Image 1: Vựa Táo via Unsplash]
[Image 2 and feature image: Shiwa ID via Unsplash]
[Image 5: Laurenz Heymann via Unsplash]

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