'iPhone slow': The truth about iOS updates

stack of old iphones
stack of old iphones (Image credit: iMore)

Every year "iPhone Slow" makes headlines. So what's really going on with iOS updates and iPhone performance?{.intro}

Update: As of iOS 10.2.1, Apple has begun prioritizing battery life over performance, which will slow down older iPhones.

In late 2016, Apple made a change that brought battery life into the iOS advanced power management system. Previously, if a battery was old, cold, or experiencing power spikes, it could drain or shut off unexpectedly. To prevent that, Apple began ramping down the processor, similar to how almost all processors have almost always been ramped down to control heat.

"Our goal is to deliver the best experience for customers, which includes overall performance and prolonging the life of their devices", Apple told iMore. "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.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."

More information on why Apple slows down old iPhones to save your battery.


Last week, a story went viral that claimed Apple was intentionally slowing down older iPhones to push people to buy its latest models.The claim was based on data which shows Google searches for "iPhone slow" spiking dramatically with the release of each new model.

That's been happening for years — I wrote about it in 2014:

Since Apple is updating almost everyone at the same time, searches will all be performed around the same time. Since Samsung and other Android manufacturers are updating only a few at a time and at different times, searches will be spread out across a very, very wide range of times.

Apple has a performance team tasked with making sure older devices don't slow down. Many engineers and others in the company carry older devices specifically to test for issues. And almost everyone has parents, siblings, kids, and other family members and friends on older devices. As a company, Apple does everything it can to ensure all supported devices run iOS as best as they can.

FutureMark went on to test raw processor performance of a range of iOS 11-supported devices:

We looked at data for the iPhone 5s first because, if older devices are being deliberately slowed, the effect should be most obvious with models that have been around for longer.The chart below shows iPhone 5s GPU performance over time. Each bar shows the average 3DMark Sling Shot Extreme Graphics test score calculated from all results submitted during that month. A higher score indicated better performance. The bars are coloured according to iOS version.As you can see, iPhone 5s GPU performance has remained consistent from iOS 9 to iOS 11 with only minor variations that fall well within normal levels.

What this shows is that Apple doesn't artificially slow down processors on older iPhones. It doesn't show how well Apple or app developers optimize code for those processors.

So, while it's great FutureMark is helping to dispell the dumbest of the dumb stories, there's still a lot of work Apple can do to improve things like frame-rate and interaction speeds on older devices. That's typically what happens in the point releases. (No amount of internal testing can come close to the data and insight you get from millions of people suddenly hitting the new version.)

Clean installs can help with that as well. I still install clean every year, even though it's a pain in the apps, and I still feel like I get better performance because of it.

Either way, "iPhone slow" simply isn't a thing, even if every year, every forum and click-site tries its best to make it into one. So, if you ever hear a friend or family members asking about it, explain it to them. And if they need help troubleshooting specific issues, just send them iMore's way.

Rene Ritchie

Rene Ritchie is one of the most respected Apple analysts in the business, reaching a combined audience of over 40 million readers a month. His YouTube channel, Vector, has over 90 thousand subscribers and 14 million views and his podcasts, including Debug, have been downloaded over 20 million times. He also regularly co-hosts MacBreak Weekly for the TWiT network and co-hosted CES Live! and Talk Mobile. Based in Montreal, Rene is a former director of product marketing, web developer, and graphic designer. He's authored several books and appeared on numerous television and radio segments to discuss Apple and the technology industry. When not working, he likes to cook, grapple, and spend time with his friends and family.

  • Ok, forget the words, "intentionally slowing" and "deliberately slowed" for a moment. Apps take longer to load on my 6 Plus after iOS 11. This will all be a memory after November 3rd though lol!
  • Whether or not they do it deliberately (I'm sure they don't)...iPhone slow is a real thing...I have proof in my iPhone 6s Plus...It's a completely new phone, and not in a good way. You can say it's 1.5-2 years old, but Apple is still selling them for $550...That's a really nice Android phone, brand new... I moved to Apple from Android for smoothness and quicker updates, and right now I'm ready to jump ship if this is the direction iOS is going. Also, why on earth should we have to wait until iOS 11.1 for a decent experience? Why did they release an unpolished product? Let me downgrade for the time being then...Oh wait, 10.3.3 is no longer signed..
  • Why, O why, do people jump on a new OS release the very day it comes out? OF COURSE there are going to be problems. But "slow downs" and battery life issues should be expected. There is some "housekeeping" when a new OS is installed. The device may even run much warmer than normal. Just let it sit for a few hours/ overnight, whatever. Everyone wants to jump in and start using it right away. Just relax and let it settle down. Personally, I am still on 10.3.3 on everything. I have a 6s plus, an iPad mini 4, and 10.5 " and 13" iPad pros. What is the rush? It is endlessly entertaining to watch you folks breathlessly downloading/installing the latest version and then complaining about it. Did you learn nothing from the problems that 10 had when it was first released?
  • I downloaded it to try it, but they removed the signing of 10.3.3, so I can't revert. Why shouldn't I upgrade? The hardware of my phone is still upper echelon (At least on paper), and Apple is pushing the updates to my phone constantly, even if I tell it to not "Auto Download".. The bigger question is why are they putting out OSes that are slow, rough around the edges, and honestly, not their best work....Just to keep up with Android? Also, I've used DFU to install as new on my phone after the many problems I had. It's been 4 days, and still dropping frames and stuttering in most apps. My phone also gets hotter than it ever did on iOS 10 doing basic tasks. My point is, lets not keep giving Apple a free pass on this. I don't want "quick updates" if they're going to make my device run like junk.
  • Are you serious!? I would have expected Apple to release absolutely tested to exhaustion software! It should be tested probably on the mobile phones of their thousands of employees and only be released to the general public when working properly. No, "slow downs" and battery life issues SHOULD NOT be expected every time Apple releases software.
  • If you think that "absolutely tested to exhaustion" software is possible, then you have never written any code. The fact is, ANY .0 release of ANY software is, in fact, a test version. That's why 11.0.2 is here already. I have been in software development for many years. We have a saying: On Time, Bug Free, Under Budget. Choose 2. And that is just for application software. An OS is infinitely more complex. Yes, there will be problems. Always. That is why I am never in a hurry to upgrade the OS on a perfectly working system.
  • You are spot on: I have never written code. I have no idea even how it's done. Honestly. But, please, do not tell me that a new software release must always be a bad one. As far as I understand, betas are released exactly to give tech savvy people like you the chance to identify and help to sort out any bugs. And then when everything is working as it should, there's a release for the masses - to which I belong. I moved to Apple products nine years ago exactly because they were different from Windows. I did not want to tinker my software. Don't even know how to do it! Apple offered me a 'closed' system that was highly efficient, free of viruses and that just worked. Now, everytime there's a new iOS version, my mobile phones slow down and the battery consumption goes crazy. With iOS11 things just became totally absurd. I listen to radio on my iPad mini through the night. With the battery fully charged, I would wake up in the morning with more than 90%. When I upgraded to iOS11 it went down to 8% (eight percent)! Both my phone and my iPad became sluggish. As always, I started switching off anything that was not essential (things that remained switched on throughout iOS10's life). Yes, battery life has improved and my machines are now less slow. What makes me mad is having Rene Ritche basically saying that we are lying! BTW, go and see how many posts by Rene Ritchie you'll find here advising, after every new iOS release, that we switch off almost everything on our mobile phones in order to improve their performance. But this time over he decided that the best thing to do would be to call us deluded...
  • Rene is free to write whatever he wants. We are free to not believe 75% of it. All I'm saying is you should wait, and see what the early reviews are. If there are multiple reports of problems (hint: there nearly always will be), then you just saved yourself from problems. Look, if you want to a pioneer, then by all means jump in first. However, as a pioneer, you should expect some arrows in your back.
  • Why do you shame people for upgrading to the latest OS when Apple encourages it and they run a beta program for months before an official release?
  • Where did I "shame" anyone? But - again - this is reason #16 why I'm still on 10.3.3. I am in absolutely NO hurry. Everything is working fine.
  • You’re blaming people for their issues rather than the company who issues the updates. The reason people update day 1 is because if nobody upgraded we wouldn’t progress. That’s why people upgrade when these updates are released. And because Apple encourages them to do so.
  • I suppose if Apple encouraged you to stick your finger in a light socket, you would do that too? Use some common sense. Any .0 release is a risk. Just wait a few weeks for the .0.3 version or something.
  • That is easily the dumbest logic I've ever read. Try an example rooted in actual tech and not an off the wall one with zero relevancy to the discussion. Apple literally spends months issuing public and developer builds of their software for people to use, test and report back. They aren't blindly shipping this stuff. If everyone followed your advice and waited, what do you propose would happen? The whole "don't update" advice is extremely poor advice. Especially considering security patches are often baked into OS upgrades.
  • That would make sense if they didn't 1. internally test it, and 2. have the beta out for months to address bugs. It seems like it has gotten buggier since launch compared to when I used it on beta.
  • Pointing to extremely focused benchmarks (i.e. those that exclusively exercise the CPU/GPU) as proof that older Apple devices are not slower after iOS updates is missing the point -- of course the hardware itself is not slower. When people complain that their iPhone is slower, they mean that the *experience* is slower. While my iPhone 6 doesn't seem to be appreciably slower after upgrading to iOS 11, my iPad Mini 2 (the first retina one) seems to have taken a huge hit. And unfortunately, the performance issues seem to be centered around the very features iOS 11 brought to the table: the new Control Center, multitasking view, etc.
  • Your phone will resume operating like it used to after some period of time for housekeeping. You should see your phone operating back to normal speeds in 3 to 4 years.
  • Yeah! I am sure that I only imagined it all. Fully charged mobile phone at 9am. By noon, after barely using it, the battery would be at around 60%. The mobile WAS slower! Started resetting and switching things off. Now, Rene Ritchie finally confirmed it: I and hundreds of thousands (maybe millions) of others were imagining it all. "iPhone slow" simply isn't a thing. Phew! Thanks iMore!
  • Obvious Shill, or AndroidCentral troll is obvious, Fanboy more? did you even read the article? wait.. don't answer that...
  • "But "iPhone slow" simply isn't a thing,.." Are you saying iphones don't slow down over time and people are imagining it? If their phones aren't slowing down, why would they search for the topic?
  • what he is saying is, Apple is NOT intentionally putting code into new operating systems to purposely slow down older phones just to get you to upgrade.
    as OS updates come, they require better hardware to run it. Will an intel core 2 duo from 2006 run Windows 10 as efficiently and a quickly as an i7-7700K 4.2Ghz QC?
    No it will not. Same thing happens in phones.
    The A8 in the iPhone 6 is a 2 core, 20nm with 64KB, 1MB, 4MB L1,2,3 cache.
    The A11 bionic is a 6 Core, 10nm processor with 32KB, instruction set, 32KB data, and 8MB L2 cache and no L3 at all.
    Geekbench shows the iPhone 6 Single core at: 2373 the iPhone 8 at: 4239, nearly twice as fast.
    Multi core cores; iPhone 6 at: 3979 and iPhone 8 at: 10405
    So is the iPhone 6 slower? yes.
    When apple designs their latest OS, do you want them to take advantage of their Good processor or design it to run on the lowest common denominator like Android?
    What's the point of making a new OS each year if apple has to keep designing it to be super fast on 4 year old hardware?
    No thanks. Design for the A11 and People can upgrade or get over it.
  • Remember when we were told that the 64 bit architecture in the iPhone 5S was supposed to future proof our devices though? So which is it?
  • Here’s the thing, my iPhone 7 Plus has absolutely slowed down since iOS 11. That’s after giving it a week and doing a full hard reset. Loading the iMessages page to send attachments and things like that take a lot longer. Not just on my device but on my mother and brothers iphone 7’s as well. Im not saying Apple is intentionally slowing anything down. Just that the experience of myself and those around me is that iOS 11 has slowed our devices down.
  • My 7 is also slower. There is a noticeable "lag" in certain apps (apples own) and just moving around throughout the UI.
  • and for every person that says this, there will be someone like me with the iPhone 7 that will say iOS 11 DID NOT slow the phone down one bit.
    But, I also did a DFU restore and put a Clean install and redownloaded my apps and did not restore from back up.
    Literally as fast as the day I took it out of the box. 12 months ago. there is no "lag" anywhere in the OS. Runs absolutely perfect.
  • Read my comment again. I spoke on my experience and those around me. For what it's worth, I also work in wireless and there have been quite a few customer complaints after upgrading. I think we all know everyone isn't having issues. But people are. We shouldn't dismiss that because your individual device runs fine.
  • No more than you should assume a few personal cases means there is an endemic problem.
  • Again...read MY comment. I spoke to MY experience and that of those around ME. I never said there was a wide spread issue. Just that I’ve personally seen a lot of complaints.
  • Obviously there’s a lot of indexing and other housekeeping type things after a new install, so some INITIAL degradation in performance should be par for the course. Although perhaps what impacts my device performance more is that I’m so busy rebooting and trying to get mobile data to work after leaving a WiFi area.
  • A week after installing iOS 11 (now on iOS 11.0.2), my iPhone 6 still stutters when switching between apps or loading them. Whatsapp, Tweetbot, Dropbox, Notes and other daily used apps take a little longer to launch. To me, iOS 11 slowed down my phone. When I was on iOS 9.3 (didn't install iOS 10) it was definitely faster.
    Regarding battery life: It's weird to me. If the iPhone is locked and I glance to notification center several times, battery remains steady, even when airplaying to Apple TV with Prime Video app or live games from the internet using Safari. Once I start using Instagram, Safari, Tweetbot, Youtube, battery starts draining faster than before.
    Anyway... There isn't much I can do, just hoping some new release fix it magically.
  • In recent times, I don't know if it was late versions of ios 10 or new ios 11, but my 6s+ takes about a 10 second delay from selecting "share a contact" or "share a tweet" for the message options come on screen. I don't think this issue is being orchestrated by the spirit of Jobs, just rushed, poor programming.
  • Rene: Have you tried iOS 11 on a 5S or 6? I haven't. I see comments. Ars does test the last supported model, but I don't think they finished yet. Truthfully, I only know one person with a 5S. I have a 6S and I haven't upgraded due to battery rumors. (To any reader encouraging me not to upgrade, don't worry, I know. I'm waiting.) Point being I don't know how iOS 11 will effect my phone. I really would like to see a true investagation into the battery issue and *interface* slow down by iMore. This is a commmentary on the media, which have not done any independent research, which has not been done here either. (I do think the criticism is deserved of those headlines, and I do not mean this as criticism of iMore.)
  • I can't relate why you can based on GPU performance and some fictional thoughts to strike out the "iPhone slow" issue. Should look at the CPU test first, or at least it should proof that CPU benchmark has not degraded. I hope you understand the different role between CPU and GPU... No offense.
  • I love when iMore or Android Central gets all high-and-mighty, and accuses other places of being "click-sites" or spreading hype. Physician, heal thyself.
  • I don't think Apple's doing anything intentionally to slow down devices with a big upgrade like iOS 11. I do think the user complaints about speed problems, battery life issues, broken features and other issues are absolutely valid. These are not contradictory positions. As I often do early in the upgrade cycle, I'm seeing problems with my own devices - problems that haven't been remedied by the usual "backup and restore" nuke and pave process. It's a good incentive for those who haven't upgraded to sit on the fence for a while longer.
  • The fact is, my Iphone 6 is very very very slow #slowIpnone
  • Run a bunch of hyper-focused benchmarks that do the journalistic spin for you. Genius!!
  • My iPhone isn't slow. However, I am having issues with Bluetooth and also...disappearing icons. I usually restart my phone to fix it. Maybe I'll reset the whole thing this weekend...see if that fixes it.
  • And for me it´s a fakt: I´m for example not able to play a podcast in the background and play pokemon go
    - no way and it worked fine on previos ios 10. -> IPhone 6Plus 64gb.
    Also carplay is terrible slow compared to ios 10 No issues on 5s and 6 of children
  • I'm glad this test was done, flawed as it was (or, rather, the presentation of the results is flawed). The CPU/GPU will give the same IOPS regardless of OS level, so a score of 750 (I'm making these numbers up) on iOS 7 will yield... that's right, 750 on iOS 11, all other things being equal. Are the phones slowing down? Technically, yes, and it's because the OS and/or the apps, not some malicious conspiracy. Will iOS 11 be slower than 10 on an older iPhone? Yes, since Apple's adding more to the OS and asking more out of the hardware -- imagine adding another 1-5% resource utilization per service (background processes) and/or an extra 1-5% running services for every new OS release and it's obvious that the older hardware will struggle. Now, couple the above with the fact that updated apps are using more resources (be it RAM or CPU/GPU cycles) and there's your slowness. I ran this test on a Nexus 7 (2013) tablet -- clean OS install (back in 2015) and just a few apps. It ran beautifully for about 18 months, and now it's a dog; the only changes have been updates of ALL of the installed apps (there were no more OS updates as of 04/16 or thereabouts, so you can see how pronounced the issue can be with just apps). Oh, also, something both Android and iOS users can universally agree on; the Facebook app is the WORST resource hog imaginable... but that's another rant...
  • Apple seems to be going in a different direction now. Software upgrades is full of bugs and releasd to early. Then there’s the iPhone x with a terrible notch that developers have to work around. There’s a lot of whoa and amazement from this site but it’s not universal for sure. Google has a compelling phone and Android has some good offerings. I’ll keep my 6s plus for another year and hope Apple convinces me to stay.
  • It's a new OS RELEASE and version (iOS 11) this happens every single year... a new OS comes out. I'm really having trouble understanding why people are NOT understanding this... Do you guys NOT want the OS to be different or do anything different at all?.
    I mean sure, Apple could come out with a "New OS" number, just call it iOS 11, and not change a single thing so that way all phones run the same way because the OS Didn't come out with new features.