Iphone 3GS slow after update to iOS 5

My 3GS had the slow response, high CPU usage and battery drain problem after the upgrade to iOS 5.0. I turned off Calendar Notifications which fixed it. When the iOS 5.0.1 update came out I upgraded, turned on Calendar Notifications again and it's been fine ever since.

I'd suggest taking the phone to an Apple Store or sending them feedback directly via http://www.apple.com/feedback/iphone.html

I do not believe there is any inherent slowness in the 3GS with iOS5. My personal experience is that in general it's just as snappy now as it was before I upgraded. This is good news because it means that the hardware itself can handle iOS5 just fine. BUT... BUT periodically it does get very laggy for no apparent reason, and then reverts to normal behaviour. I think this points to background processes misbehaving or network activity getting in the way. Hmm, I wonder if it depends on the carrier...?

Have found a way to downgrade to 4.3.3 for those interested:

http://www.youtube.com/watch?v=uDYQTssWyV0

iOS 5 will slow your iPhone 3GS down because your phone only has a 600 MHz processor and 256 MB of RAM. The iPhone 4S has a DUAL CORE 800 MHz processor with 512 MB of RAM. iOS 5 is made to utilize both the A5 chi anf the 512 MB of RAM. iOS takes up a lot of your available RAM space so it won't run as smoothly as it did before iOS 5 or even iOS 4.

Hi Matirx: all that you say is technically true; however, in terms of actual user experience, I find that the 3GS is plenty powerful enough to run iOS5 with no noticeable slowdown compared to iOS4. It's possible (probable in fact) that with certain apps it will run out of steam but I haven't found that to be an issue so far.

It is true that there are some occasional hangs and hccups but it appears that they are due to iOS5 itself and iCloud, rather than due to limitations of the 3GS. Presumably those issues will be fixed with updates.

YMMV of course but personally I'm delighted I saved the $500 early upgrade fee and stayed with the 3GS. I was on the verge of buying the 4S - I even paid the reservation fee (refundable fortunately) - but when I saw how well iOS5 works on 3GS I decided to save my money for iPhone 5 next year! Oh, wait, I already spent it on upgrading my MacBook Pro to a MacBook Air... - I guess all the money goes in Apple's pocket in the end, one way or another!

Well, that's a given.

And we all know that they knew the technical shortcomings before they even put out the iOS update. The responsible thing to do would have been to bar the 3GS from be updateable. All I'm asking for now is a downgrade back to ios 4.

I downloaded the 5.1 fix and now my phone is almost inoperable.

And I have never run iCloud. I disabled it as soon as I updated. My phone has tremendous lag and many times freezes completely.

I would love to know what people are doin that keeps their phones "snappy" as ever.

Sccrbrg, re "The responsible thing to do would have been to bar the 3GS from be updateable."

I certainly hope not! I've got at least an extra year of use, maybe two, by being able to use iCloud on my 3GS (as well as other new features - but iCloud is the biggie).

It's a mystery why some people have no trouble with iOS5 on 3GS, yet others find it so slow as to be unuseable. There has to be a logical explanation The hardware is identical, the OS is identical. The only variables I can think of are: (a) the user-installed apps or (b) the carrier...?

Worked exactly as described. Did not need to Restore.

Thanks

what do you mean? what steps have you performed?

Sorry -

Replied in post. See below.

AnaMusic

Level 5 (5,010 points)

This is so frustrating. We have 2 iphone 3GS's. Both operate on the same itunes account but with different libraries. One is linked with iCloud and in oreer to get that working correctly I had to purchase extra calendar software. Thought I'd just got everything going ok but kept finding that the apps and texts etc were sos so slow. The other 3GS which isn't linked to iCloud at all has the same problem. Both on iOS5 - wish we hadn't upgraded. Drives us batty - even just swiping to unloack can take so long. When texting we are lines ahead of on the keyboard. Started to use talk to text instead now - as that is quicker.

, for both emails and texting! Really am not at all happy. SLOW, SLOW, SLOW. .... and yes - I have followed the links to reset, restart with no effect, and no I am not turning off apps and icloud and wifi sync - well not permanently anyway - when they are off the phone is a teeny weeny bit quicker - but not enough to warrant loosing the facility. "Update fix needed quickly Apple!!"

Just as an experiment, what happens when you turn on airport mode? Does the slowness go away?

I've been monitoring this thread and what strikes me is that some people report the 3GS is perfectly fine while others experience extreme slowdowns such as yours. There is so far no apparent reason for these radical differences and I'm starting to wonder whether it depends on the carrier. If that's the case, going into airport mode should (temporarily) fix it. anyhow, it would be interesting to try.

By the way, what country are you in and what carrier?

I'll try that - my husbands phone is on TMobile (not linked to iCloud) and mine is Orange.(Wifi syncing and icloud) We are in London, UK.

- Nope - no difference - which is just as well, as it'd be a pretty lousy phone in airport mode all the time! Notice also that a simple page scroll is so delayed - it's so annoying!!

OK, so far so good with the detective work. I am with Rogers in Canada. So here we are with my 3GS running just as snappily as ever and yours running slow as molasses. I know that carriers are in the habit of customizing the phone software for regular mobile phones (or maybe it's in the SIM?) - I wonder if it's conceivable that UK carriers are doing something to the iPhone software that creates issues in the 3GS running iOS5? Such issues could persist even when the phone is not connected to the network.

So here's a more general question: those who are experiencing molasses, what is your country and your carrier?

Hmm, it's also conceivable that the actual phone hardware/firmware is different for phones sold in the UK versus those sold in Canada. That could be another reason for the difference. Detective work continues...

I'm coming to the UK for Christmas and it will be interesting to see what happens to my 3GS performance when I'm there! Even more interesting would be for me to plug my SIM card into your phone and see what happens but unfortunately that wouldn't work because the phones are locked to a carrier.

I'm in the US on AT&T