iPhone 6 very slow with IOS 11 update

elppadaed wrote:

Does anyone know if ios 11.2.1 will fix this issue?

In my case 11.2.1 did not fix the issue. I still see performance degrade when my battery level reaches 90%, and then degrade further as the battery level drops into the 80's.

My old iPhone 4 that I kept as the house phone, and iPhone 5 performs better than the iPhone 6 because the old Apple wisely stopped updating them because they don't support the higher demands of newer iOSes. 11.x is now obviously too demanding for iPhone 6x, and Apple shouldn't have rolled it out.

The right thing for Apple to do in 11.2.x is to address the iPhone 6 slow down issues, and disable the frills for iPhone 6 users so that their 2 year old phones are still usable and are not slower than their grandparents' iPhone 4 or iPhone 5.

What's eating up all the memory in iPhone 6 (1gb RAM) anyway in iOS 11?

Since the exact same 3rd party apps are slower in iOS 11. Its a classic sign of the OS not having enough fast RAM, and is constantly swapping out to VM. Eventhough the storage is solid state, it is still many times slower than RAM.

The problem isn't caused by fancy features of iOS 11. It appears to be the side-effect of a bug fix.

In the iPhone 6 (and possibly 6s), the CPU would sometimes spontaneously shut down when batteries began to age. You'd be using your iPhone, and it would suddenly shut down (or restart) without explanation. The batteries weren't supplying sufficient voltage to keep the CPU chugging along.

As of iOS 11, iOS detects the battery issue and in response it under clocks the CPU. On my iPhone 6, when the battery reaches 90% charge level, the CPU goes from 1125 MHz down to 800 MHz. When the battery charge level goes down to around 85% the CPU starts operating at 600 MHz. Note that the CPU is rated to run at 1400 MHz.

Not surprisingly, the lower clock rate has a bad affect on performance! Personally, I'd rather have my phone shut down once a month if in return it worked fine the rest of the time. Instead I have a phone that performs poorly almost all of the time.

Hopefully Apple will come up with some other way to address the problem.

This was the consensus view of a recent discussion on Slashdot, and it's the most plausible explanation I've seen. It explains why my CPU clock rate gets lower and lower as my battery charge level decreases.

See this comment, for the clearest summary of technical issues.

https://apple.slashdot.org/comments.pl?sid=11472415&cid=55724579

I'm still unhappy with the situation, and hope Apple finds some other way to address besides crippling my phone. If there was a design problem with the battery and CPU pairing requiring them to do this, they could at least acknowledge it.

Do you guys want to laugh at a good joke ?

Watch that (at 18min) https://youtu.be/38IqQpwPe7s?t=18m

It’s the iPhone 6 presentation keynote 😂

Thank you Phil, you just lost all your credibility in today’s context.

Maybe only part of the RAM chips are actually powered on to save power, maybe you can run to the full 1 GB for the front app only and if an app goes in the background its memory is flushed (I don’t thing it’s swapped at all for apps because you can see them (as safari tabs) reload like on a fresh start

So I wouldn’t be surprised that the phone runs on only 512MB most of the time.

+ don’t forget underclocking also affects the RAM frequency.

Visberry wrote

"WOW! when did you figure that out? "😮

That was in response to 'Allmight', but for some dumb reason this message board chooses when and when it won't post in the right order. Stop being so Patronising.

The problem isn't caused by fancy features of iOS 11. It appears to be the side-effect of a bug fix.

...

Hopefully Apple will come up with some other way to address the problem.

This sudden death affected my wife's iPhone 6 plus that Apple recalled and changed the battery. It was fine thereafter for a while, then it started again, especially in cold weather (skiing). We decided to sell the phone.

I doubt Apple will fix this bug fix ⚠. Its between Apple getting complaints of sudden death and people complaining such as in this forum that their phone is so slow its frustrating and unusable. Apple is not known to admit to a mistake and provide, say a 'feature' to disable the throttling. But I could be proven wrong.

There are a few things you can do when dealing with a slower iPhone

1. Restore your settings as someone in this thread mentioned.

2. Make sure that you have some space left, devices tend to be slower when they are full.

3. There are some settings can turn off animations, transparency...etc. Changing these may significantly boost speed.

One last thing, not about users, but about Apple. Apple's decision put 1GB of RAM in iPhone 6/iPhone 6 Plus is a huge mistake. 1GB is the same as iPhone 5 and iPhone 5s, but iPhone 6/iPhone 6 Plus has much higher screen resolution. The ultimate solution then is to switch to a newer device.

I got a battery case for my iPhone 6. So far so good. My iPhone's internal battery is now pretty much always at 100%, which keeps the performance problems at bay. The cost was about $15. It's a little bigger than the previous case I had, but it's worth the tradeoff.

So,

It turns out that iOS 11 issues on iPhone 6/6s ARE battery related if you are no longer experiencing iOS 11 performance issues using a battery case that is keeping your iPhone 6 continuously charged at 100%

Kinda confirms Visberry’s hypotheses on iPhone 6/6S degraded battery isuues causing the poor iOS 11 performance.

Looks like Visberry’s theory/hypothesis on iPhone 6/6S battery issues affecting iOS 11 performance were “spot-on”!

Fixed!

I finally found the culprit (I think)!

I changed the battery for a new one as suggested here and now the phone runs smooth again.

I imagine apple charges around 90 ~ 100€/$, but I bought it in ifixit for around 30€ with all the tools needed to do it myself.

It's not a procedure for the faint hearted tho, I must have given the screen an electrostatic shock or something and 4 vertical lines appeared in it. I was so worried... but they seem to be dissapearing as time goes by. Phew.

It's worth it tho, i was about to sell it.

It's been two weeks since I replaced the battery in my 6 plus, 64GB iPhone and wanted to provide an update. Performance has remained significantly better since the replacement; however, there are definite correlations between performance and battery state. When the charge is below 50%, there are very noticeable performance hits, especially with scrolling down pages and lists; iMessager is slow to respond, the native email app is degraded, and screen orientation definitely takes a hit. I rely on this phone for business and there are times when I want to toss it out the window when I'm stuck waiting for a process to complete before the app returns. As I posted in previous threads above, I have restored this device to a native state and re-installed just the essential apps from the iTunes store. I have over 40GB free storage, and I've disabled most, if not all the "fancy" features. So, in conclusion: a fresh battery will definitely improve the overall performance and make the phone generally usable, don't expect that to restore it to it's previous Apple glory.

mjestic wrote:

It's been two weeks since I replaced the battery in my 6 plus, 64GB iPhone and wanted to provide an update.

Thank you, that's very thoughtful, and the information you provided is very helpful.

Performance has remained significantly better since the replacement; however, there are definite correlations between performance and battery state. When the charge is below 50%, there are very noticeable performance hits,

If you want, you can measure this effect by getting a an app that measures CPU performance. One example is CPU DasherX. I found that when my battery level drops to certain specific levels, the CPU clock rate drops. For example, it initially runs at more than 1100 MHz, but then drops down to just over 800 MHz when the batter charge goes below 90%. It was nice to know I wasn't imagining things, and also to demonstrate clearly that the performance problems are related to battery level.

One way to address the problem is to buy a battery case. You can get these for as little as $15. They are a little bigger than a regular iPhone case, but for me it is worth the tradeoff. If my iPhone battery starts to go down I just push a button on the back of the case and the phone charges back up to 100%. So I pretty much never have to deal with the performance issues.

especially with scrolling down pages and lists; iMessager is slow to respond, the native email app is degraded, and screen orientation definitely takes a hit. I rely on this phone for business and there are times when I want to toss it out the window when I'm stuck waiting for a process to complete before the app returns. As I posted in previous threads above, I have restored this device to a native state and re-installed just the essential apps from the iTunes store. I have over 40GB free storage, and I've disabled most, if not all the "fancy" features. So, in conclusion: a fresh battery will definitely improve the overall performance and make the phone generally usable, don't expect that to restore it to it's previous Apple glory.

Thank you again for sharing your experience. It's very helpful information.

For all those wondering if a new battery will solve the problem, Geekbench just posted a blog on this very issue:

https://www.geekbench.com/blog/2017/12/iphone-performance-and-battery-age/

I've already confirmed this issue on my (basically useless once I get lower than 90% battery) iPhone 6. At this point, it's pretty obvious what's going on here...

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Note, this post was edited by Apple.