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Will iOS 9 slow down my iPhone 4s or iPhone 5/5s? Perhaps a little (Video)

Screen Shot 2015-09-23 at 8.36.13 PM

When Apple releases a new version of iOS, owners of previous generation devices are always a tad hesitant to upgrade, worried that the added features will bog down their device and make it run slower than it originally did. While iOS 9 has been the quickest adopted version of Apple’s operating system yet, there are likely still some holdouts worried about device performance. YouTuber iAppleBytes has this evening shared videos comparing the performance of iOS 9.0.1 to iOS 8.4.1 on the iPhone 4S, iPhone 5, and iPhone 5S…

The general consensus throughout the three videos is that overall, general device performance has taken a step back with iOS 9 on the iPhone 4s, 5, and 5s. As you can tell in the videos below, the device that appears to suffer the hardest hit in terms of performance is the iPhone 4S. That’s to be expected, however, seeing that it was released all the way back in 2011.

All three videos show a general added layer of lag with iOS 9 compared to iOS 8.4.1. On the iPhone 4S and iPhone 5, the boot time was increased by several seconds with iOS 9, while it is nearly the same on the iPhone 5S. Camera performance across all three devices is slightly slower with iOS 9/iOS 9.0.1, although there’s a very small difference with the iPhone 5S. One point of improvement, however, appears to be in the performance of Siri. Apple’s virtual assistant was quicker to respond in almost every instance with iOS 9 than it was with iOS 8.4.1.

Our own poll from last week shows that 36 percent of users are experiencing “significantly” slower performance after updating to iOS 9, while 31 percent say their device is “a little bit slower.” Today’s videos, however, do show some minor improvements in iOS 9.0.1 compared to iOS 9.

Earlier this week, Apple stated that iOS 9 has already been installed on 50 percent of devices, giving it the fastest adoption rate of any iOS release to date. The release hasn’t been without its issues, though. iOS 9.0.1 was released earlier today, however, in an effort to squash some of the more severe bugs that users have been experiencing.

You can view iAppleBytes’s videos comparing performance on iOS 9.0.1 to performance on iOS 8.4.1 below:

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  1. Abraham Song - 8 years ago

    It’s slowed down my iPhone 6 Plus slightly. When I go into the multitask switcher, you can clearly see frames being dropped as going through the apps isn’t as smooth as it used to be. I like the update, just don’t like the stutter.

    • sulfen - 8 years ago

      The stutter went away on the 9.0.1, at least I haven’t seen it happen since I updated it.

      • ockali - 8 years ago

        I also experienced a performance boost with 9.0.1 to how it used to be with iOS 8.4.1 on my iPhone 6. The original iOS 9 felt rather sluggish in comparison.

      • Abraham Song - 8 years ago

        I still have the stutter unfortunately.

  2. smartysanky - 8 years ago

    Just wait for 9.1. I am running it on a 5S and it runs buttery smooth. Don’t understand why Apple decided to keep such performance improvement for another update.

  3. srgmac - 8 years ago

    Hm…I have the 5S, I haven’t noticed any kind of slowdown of anything…YouTube crashed a few times though since upgrading — so did some other apps, they just seem to randomly crash and that did not happen on 8.X.

  4. purpleeblush - 8 years ago

    The IOS9 update has increased the battery life on my 4s – the ‘low power mode’ works well for me.

  5. swe3t23 - 8 years ago

    did you guys update on a fresh iPhone 5s. i usually do a clean restart (a hard reset as if it was brand-new) then update when a major update is available like the ios9

  6. harotukan - 8 years ago

    Anyone else having problems with battery up time on iOS 9.1 running on 5S?
    Just by the time I was typing this comment I lost like 7% of my battery. And I am not a slow-typer :D.
    Not getting over 4 hours of real-time use.

    • Kevin Neal - 8 years ago

      I’m seeing a massive improvement in battery life on 9.1 beta 2, my phone was needing to be charged 3 times a day, now I’m still at 80% after 4 hours

  7. It’s not that slow on iPhone 4S, I use one. I see the responsiveness being the same for 7, 8, 9. Yes, it could be faster but what can I expect from an old HW? It needs a new one and that’s why I’m waiting for the iPhone 6s to be finally available in my country. Maybe in 1-2 months. When I saw videos of iOS 9 on iPhone 5, 5s, 5c and 6, it is much faster on each of those so there shouldn’t be any complaining for those users.

  8. Ryann Soriano - 8 years ago

    My iPhone 4s wont open after upgrading for 3 long hours. What to do? Please kindly advise

  9. Oflife - 8 years ago

    Bare in mind I’m a veteran software developer. I have news for you, there is NO reason for an OS upgrade on any device to slow it down, unless the authors (perhaps under instruction from management) intentionally knobble the code, insert inefficiencies or are just bad coders. My company has been developing software since the 1980s ( and back from the days of computers with a few K of RAM, we optimised our code such that the very opposite happened, our upgraded apps were faster on the SAME hardware, and of course, much faster on new hardware, but NEVER did an upgrade slow anything down. I have owned a Mac since 1990 (Mac Portable) and also a few phones and PCs, and this issue of OS and upgrades slowing old hardware down always occurs once my host device is more than about 2 years old, which fits in with the (not made public) fact that device manufacturers want you to upgrade your hardware every two years or so. And it’s the same with our increasingly unreliable white goods. Long gone are the days of a 10 – 15 year appliance or computer. You’ll learn as we have with the VW issue that no matter the public face of some companies, embedded within their management (perhaps even the CEO’s office!) are nefarious people who only think about the bottom line.
    I will let you dear 9to5ers read into this as you like, but don’t let the Apple fanboism detract from the fact that Mr Cook and his team are business people – after all, TC was a supply chain wiz before his upgrade. That is why Apple did not put wireless charging in the iPhone – they want you to go out and pay silly money for extra docks and cables. Me? I bought a Grade A used Nexus 5 for 1/3 of the price of an iPhone 6s/6+ along with three wireless chargers, for a total of £250. Tough grippy case (no need to spend £30 on a protective cover), wireless charging, NFC, pretty good camera (since firmware update), very very fast OPTIMISED version of Android Lolipop. In fact, it does all the latest iPhones do minus 4K video, which the new Nexus will do.
    I do believe Google engage in this intentional slowing down of upgrades on old hardware. I have owned multiple Samsung and Nexus phones, and whilst the Nexus always remained snappy after an update, the Samsungs did slow down, so I think they also engage in this un-optimisation.
    In conclusion, want a device that lasts quite a few years and gets faster, get a Nexus. Want the bling? An iPhone!
    (Typed on a 13″ MacBook Pro Retina 2015 edition, because when it comes to laptops, Apple are still the daddy.)

    • Oflife (@oflife) - 8 years ago

      I made a MASSIVE typo above. I meant to say “I do NOT believe Google engage in this intentional slowing down of upgrades on old hardware.”

    • standardpull - 8 years ago

      simple traditional OS will generally get faster with time if all its features stay the same. But you’re talking about a feature-neutral OS update, like going from MS-DOS 4 to MS-DOS 5.

      A -real world- OS upgrade includes news features and more sophisticated features. This often results in more additional background processing and more complicated services. Layer in some new search engine tech and some new AI and some new fancy “always on” 3D graphics, and that’s going to have a real cost in terms of RAM consumption and CPU utilization. Add more robust security checks inside the OS is going to be another big hitter.

      Hopefully, when adding such features one can also optimize less efficient pieces of code: caching, writing critical routines in assembler, pushing code into the hardware, etc.

      But to pretend that a living, breathing OS should always get faster with each release is either disingenuous or ignorant.

    • Pastor Martin - 8 years ago

      I think there’s room for a difference of opinion here. I think I’m finding as mobile devices reach a certain level, Apple is keeping them updated longer and the updates are running smoother. I’m typing this on my iPhone 5S running 9.0.1 and it’s running beautifully.
      And regarding there being no reason at all, would you include things like multitasking and fancy graphics effects? Because I don’t only notice this slowdown in OS upgrades. My DAW studio software has increased hardware requirements with each major update.
      The fact that they’re willing to update the 4S (a four year old phone) to iOS 9 and it’s running it without major issue (I realize there are some commenters having some issues but this is 9.0 and 9.0.1 we’re talking about, it’s brand new) undermines your argument here, doesn’t it?
      Not trying to troll, just another perspective:)

    • SKR Imaging - 8 years ago

      I tend to disagree.. my iPhone 4S is running quite well for a 4 year old device with iOS 9… of course there is slowdown when switching between apps but that is to be expected from a 512MB RAM device.. My iPad 3 aswell is running better on iOS 9 than on iOS 8.. and that device has not gotten much love from Apple since i was released.. getting to keep my 4 year old phone and 3 year old tablet is great… My Android using friends are still on a 2 year old OS (no more updates being available from the manufacturer).. and I tried some of their phones and find them unusable in terms of sluggish performance. and they bought their device 2 years ago.

    • Bjarne Dahlberg - 7 years ago

      I find it very odd that with EVERY iOS update since i bought my iPhone 4s it is became very slow just after a new iOS was released??Explain that andf after the update it became faster but not as fast as it was on the first one that was installed when i bought it brand new.
      And after the new iOS release i am bombed with notifications that i need to upgrade iOS
      If i like my OLD system it is I who decide if i want to upgrade not nazi-apple.
      And you said it perfectly well “there is NO reason for an OS upgrade on any device to slow it down, unless the authors (perhaps under instruction from management) intentionally knobble the code,”
      My guess is that they insert some timebombs or whatever in the code so the phone became slow.
      And since it happen to alot of people well millions i guess i am right.

    • Abdulrahman Leila - 7 years ago

      Dear User,

      Might be some accusation happened while updating your phone, Try to press and hold the lock and home bottoms together for 20 minutes, It should work after that.

  10. firuqutharuphwafozurtbud - 8 years ago

    iOS 9 caused my ‘new’ iPhone 4s (only a few months of use out of box) to keep displaying a black screen every so many minutes.
    Downgraded to 8.4.1. Advised my daughter to also not upgrade to iOS 9.

  11. Jimmy Martin - 8 years ago

    One of these comparisons for various iPads would be very helpful. I’ve been holding out on upgrading my 3rd gen.

    • Mel Snyder - 8 years ago

      I am waiting too – I had to revert to iOS 7 after trying iOS 8 – ,y Zagg Bluetooth keyboard became unusable (too slow response)

  12. Joyce Matthews - 8 years ago

    Slightly different subject, it brought my ipad 2 to it’s knees, and with no notable improvements. Split screen and siri do not work on the 2. I had to revert back to 8.4.1 to get apps to respond in a reasonable amount of time.

    • joeriveranyc - 8 years ago

      Same experience here. My iPad 2 is a nightmare to use now — constant slowdown, unresponsiveness and crashing in all apps (including Apple’s own). They really dropped the ball on this update – it should not have been released for the iPad 2 if this is the level of performance.

  13. Mike Retondo (@mretondo) - 8 years ago

    I have a 5S and after upgrading to iOS 9 I had stuttering while scrolling. This is common after upgrading as Spotlight has to reindex the drive. After a few days I still had stuttering so I did a clean install and the stuttering went away in a day.

  14. I have a 4S and the iOS 9 upgrade made it significantly more stable and more functional all around.

  15. Drew (@gettysburg11s) - 8 years ago

    Interestingly, I put iOS 9.0 and then 9.0.1 on my wife’s iPhone 4S, and it seemed a little faster to me than iOS 8.4.1.

    My iPhone 6 seems the same speed, with any of those OS’s. I am looking forward to the super speedy 6s I will get on Friday!

  16. macnificentseven48 - 8 years ago

    Considering the iPhone 4S was released in late 2011, I think Apple should be given credit for allowing consumers to update to the latest version of iOS and getting fairly decent performance. I would think that’s getting pretty good bang for the buck to be able to use a four-year old smartphone with the latest iOS 9.x. I doubt most four-year old Android smartphones would be be able to do that unless they were flagship models. This ability would have to make it worthwhile the extra money to keep an updated smartphone for such a long time. Wall Street may love Android because of the market share numbers but I’m sure iOS users are getting a better experience over the long run.

    • The question isn’t about the age of the phone, it’s what’s being done to the OS to make it slower? There’s no reason launching apps should be slower. There’s no reason for springboard to be slower when extra animation options are disabled to produce the same results as a previous OS. There’s no reason for battery to drain much faster than other OS releases.

      Clearly there are priority shifts at Apple causing a detriment to certain properties of the OS in favor of certain others. Imagine how much faster an older OS would be on a new device? Age-old problem which keep things almost static – as hardware gets MUCH faster, software gets MUCH slower eating into the performance gains you’d hope to see. This is one of the reasons why synthetic benchmarks don’t paint a realistic picture.

    • Bjarne Dahlberg - 7 years ago

      apple should not have any credit whatsoever the shityest company ever only applefanboys who is the dumbest o´f the dumb dont realize that

    • Bjarne Dahlberg - 7 years ago

      Well my 4 years old HTC Desire runs much smoother than my iPhone 4s which is only 3 years old since i bought it just before iPhone 5 was released explain that apple fanboy.
      You apple fanboys needs to come back to earth and leave that sect

      • TG (@ratgt) - 7 years ago

        I am sorry for busting your bubble, but you are also blinded by android fanboyism, with a tendency for hostility towards iOS and Apple devices.
        First and foremost, fanboys are equally blinded, whether they are on planet Apple or planet Android. As much fanboyism or hatred is being shown on an Apple website, you’ll find equally much on Android websites, sometimes even more!
        Secondly, you compare your 2011 HTC Desire which has officially received maybe 1 update (and that was maybe 3-4 years ago) to the 2011 iPhone 4S which received it’s 4th major official update a couple of weeks ago, in the year 2015?!? Man, please do a reality check, because you are more of a fandroid than you realize…

  17. Daniel Robertson - 8 years ago

    You’re using a phone from 2011, how on earth can you expect it to run recent software and keep things like frame rate high. Apple gave you the OPTION if you want to install iOS 9. It’s not forced. I updated an old HTC Desire and it now barely turns on!

    • Bjarne Dahlberg - 7 years ago

      Funny my HTC desire is running so smooth it has latest os it is also 4 years old better batterytime than any iphone i know of better everything except the phone app.

      • TG (@ratgt) - 7 years ago

        Don’t be such a bad lie-spreader! It all come down to MAJOR differences for the average user/consumer: 2011 HTC Desire has hardly 1 official update and that was almost 4 years ago, while iPhone 4S received its 4th major official update a couple of weeks ago. You have to install unofficial ROMs (not from Google or HTC) in an advanced and time-consuming way in order to update to newer Android versions (NOT even the latest, as I’m sure that 2011 mobiles suck hard on Marshmallow) , while an iPhone 4S user just clicks on ‘Update’ and receives the latest of September 2015, officially…

  18. Jake Becker - 8 years ago

    My 5S has a very slight lag, but it’s not per app, just overall responsiveness of apps across the board. Generally enjoying the new update otherwise.

  19. b (@therealdesib) - 8 years ago

    The key difference for me, on the 4S, between iOS 8 and iOS 9 is that iOS 9 has smoother animations and less stuttering and lag. I found that although they have similar speed, everything feels smoother on iOS 9 for the 4S because of the smoother animations.

  20. Jonathan Hartwig - 8 years ago

    Yeah, definitely created significant lag on my iPhone 5. Obnoxious lag. After using iOS9 I can’t think of a good reason to move up from iOS8. Personally I’d advise anyone with an iPhone 5 to stay on that version if you’re looking for optimal performance.

  21. Ken Porter - 8 years ago

    I don’t plan to upgrade our iPhone 5, 5c or 5S to iOS 9, ever. Been bitten once too often with terrible slow downs on older devices.

  22. just1n12 - 8 years ago

    That’s why I have 9.1 Beta 2 lol it’s so smooth and runs great on my 5S.

  23. johnpford - 8 years ago

    I wish they would have compared it on the iPad2.

  24. MrkoDaz (@mrkodiaz) - 8 years ago

    The iphone 5s with the ios 9.0.1 look whit more lag than the normal, but my iphone 5s is not behaving slow like this :/

  25. dday408 - 8 years ago

    I got a new iPhone 6S Plus 128GB. In comparison, iPhone 6 Plus 128GB seems very sluggish under iOS 9 or 9.0.1. The performance is clearly decreased from when it had iOS 8.4.1. I put my iPhone 6 Plus to do a boot speed test with the 3 videos here, my iPhone 6 Plus starts up only slightly faster than iPhone 4S but lag behind iPhone 5 and dramatically behind iPhone 5S!!!

  26. It really boils down to people’s perceptions. Many people won’t notice much if any performance hits despite the fact there are. I noticed with each ios update my iPhone, iPad,and touch get slower. My rule of thumb is never upgrade to a higher than one level that came with your device unless you must. That’s why I’m using an iPhone 5 running ios 7 +. I have yet to see any reviews from people who upgraded to ios 9.0.1 who run the latest
    Ios 7 version. In fact people who she an older OS have issues I’m upgrading to ios 9.

  27. dphoneworld (@fabiannit) - 8 years ago

    iOS 9 is better on iPhone 4s if you dont care about slower app response but you care about in-app speed:

  28. malknapp - 7 years ago

    I installed IOS 9 on my 4S and it crashed beyond recovery. I’ve worked with Apple several times to try restore it without success. I’m out a phone and Apple doesn’t seem to care.

  29. jsearsy - 7 years ago

    I went from the 5s to the 6s a month ago and I absolutely hate it. For what I use the iPhone for I don’t really see any major difference. Then again I only use a couple apps and mostly use safari. I own the 6s outright and not locked into a contract with Verizon. I’m debating returning the 6s and getting my refund and getting another 5s. Which I consider to be the best phone Apple ever made. I’ve had them all but the 5c and 6. Any thoughts? Is the 6s really worth it for what I do in it? Thanks

  30. Karynna Lynne - 7 years ago

    It’s not only slowed my 4S down considerably, it has rendered it nonfunctional for most tasks. I had to remove two applications I actually use on a regular basis, and I still can’t take pictures or rely on Facebook working without crashing out due to lack of available memory. There’s all sorts of ridiculous crap on there now that I will never use, and which I cannot remove: instead of just music, videos, and crap about the stock market I have six or seven of these ridiculous, memory-wasting apps.

    I despise the new OS, and would love to revert to an older one– back when I could use my phone to take pictures on occasion, and to check Blackboard, and to read my email without the entire system going haywire.


Avatar for Chance Miller Chance Miller

Chance is an editor for the entire 9to5 network and covers the latest Apple news for 9to5Mac.

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