Apple slows your iPhone down "to conserve battery"

Six6siX · 22 Dec 2017 at 15:17

Nasher said:
Lol Apple...

They only use excuses like this because most of their customers don't know better. The battery life is never an issue since the user can simply pop the back off and replace it. Just like you can with an SD card. Oh wait...

HAHA!!! GOOD ONE M8!!!

Bear · 22 Dec 2017 at 15:19

james.miller said:
Ridiculous comments? Nope, lost me. Not sure what your issue is but it not my fault.

Because you are one of those particular people that seemingly like to falsely ascribe a false position to people and argue on that basis then feign ignorance about it.

james.miller · 22 Dec 2017 at 15:22

Oh so a insult on the back of an incorrect overhasty assumption, then? got it.

Back under your rock, Bear. Unless, you know, you arent just trying to troll? in that case...sorry? does that make you feel better? do you need a hug?

Six6siX · 22 Dec 2017 at 15:26

Would that be a....

Bear Hug?

james.miller · 22 Dec 2017 at 15:28

Six6siX · 22 Dec 2017 at 15:29

Bear · 22 Dec 2017 at 15:44

james.miller said:
*I* was talking about it, you responded to *me*.

The point was anything that taxes the cpu to the extent that the screen needs to be on for addition seconds / minutes isnt going to save anything by running on slower cores instead. That isnt the point of Big.Little as i explained; Big.Little is about effective management of tasks - the right hardware for the job. Decoding an MP3 is a perfect example. You dont need to use the the power hungry cores to do that. The efficient cores might take a fraction longer to do the job, but they'll do it more efficiently. Limiting the cpu frequency could shift some of the tasks that *just* would have gone to the bigger cores, to the smaller ones. Sometimes it'll still be more efficient, some times it wont. Anything that taxes the big cores though, probably wont be more efficient on the smaller cores no matter what the task is. Lower clockspeeds should mean lower voltage as well.

Ok let’s start again with a clean slate

I responded to you because you responded to Asim about having the choice about reducing screen brightness to preserve battery power (I happen to agree with him on that being a viable alternative). I’m aware of what little.big does and I agree with what you have written but what I am saying is the usage profile of a mobile device user is more dynamic than that. Playing games, web browsing, streaming video etc is screen and can be processor intensive and down clocking the processor of the phone would probably not save that much power if at all and potentially make the user experience that much worse.

I’m not talking about how the data is apportioned to which processor as I have no idea how a down clocked processor might change how that is handled if indeed it changes at all.

Anyway Merry Christmas to you

jpaul · 22 Dec 2017 at 15:47

This could be categorised as an analogue to the VAG scandal, they have been pushing the benchmark results and have discovered this leaves inadequate margin to protect against erratic shutdown (with normal applications) under ageing batteries.
In the reddit articles etc cannot see any data about folks who have had shutdowns though, where data is lost ?
(may also be scope, like vag that OS code could recognise the benchmark signature and increase performance - over volting - to the detriment of device lifespan)
LOLApple hit with lawsuit after admitting to slowing down iPhones with depleted batteries

Otherwise some of the comments in reddit are interesting, these theories stuck-out

This could be down to a couple of factors:

Apple shipped defective batteries.

Apple removed/blocked access to certain battery API's in iOS 10. Perhaps this thing could have been a software bug all along?

Apple has been pushing past the limits of silicon for the past couple of years. Battery technology isn't there yet so they have to resort to "fixes" like this

james.miller said:
The efficient cores might take a fraction longer to do the job, but they'll do it more efficiently

as an example the two cores can use different types of transistor, leakage is the key word here, you can have a high leakage fast transistor which will drain the battery faster when it is 'powered up', and a complimentary low leakage transistor that is say 20% slower but leaks at 50% of the rate of its faster colleague.... so it is an interesting trade-off.

power saving on screens Not sure if the apple oled screen can do this , but some of the rgbw screen types allow you to reduce the power to the screen, keeping the brightness, but the colour accuracy & gamut is subtley degraded.

james.miller · 22 Dec 2017 at 15:51

Bear said:
I responded to you because you responded to Asim about having the choice about reducing screen brightness to preserve battery power (I happen to agree with him on that being a viable alternative)

I think that's where we differ because i don't believe either is a good solution especially if it leaves a consumer in the situation where they can no longer see the screen in certain situations. figures of 100% and 50% brightness have been mentioned here but the reality is few people use their phones at 100% brightness for any real period of time. Mine for example sits mostly at 40 to 50%, so if the solution on my phone was to reduce the brightness, you're looking at (pardon the pun) a reduction to say 25-30%. that's a big difference and it stops me using the phone at all in any strong sunlight. That is not, IMO, a suitable solution for the battery issue. Neither is slowing the phone down. The answer, the only one, is a new battery. That, or design some batteries that actually last the distance and Apple are far from the only guilty party there.

Bear · 22 Dec 2017 at 15:59

james.miller said:
I think that's where we differ because i don't believe either is a good solution especially if it leaves a consumer in the situation where they can no longer see the screen in certain situations. figures of 100% and 50% brightness have been mentioned here but the reality is few people use their phones at 100% brightness for any real period of time. Mine for example sits mostly at 40 to 50%, so if the solution on my phone was to reduce the brightness, you're looking at (pardon the pun) a reduction to say 25-30%. that's a big difference and it stops me using the phone at all in any strong sunlight. That is not, IMO, a suitable solution for the battery issue. Neither is slowing the phone down. The answer, the only one, is a new battery.

Absolutely I agree that is the optimal solution. Sorry I wasn’t clear about the screen brightness issue, what I meant was instead of covertly slowing someone’s processor down, I would have preferred being given a choice and Asim’s solution of asking the user whether they would like to preserve battery power by reducing screen brightness or carrying on as is knowing you have shorter battery life would have been better. Having the choice was more the issue.

Bear · 22 Dec 2017 at 16:10

jpaul said:
This could be categorised as an analogue to the VAG scandal, they have been pushing the benchmark results and have discovered this leaves inadequate margin to protect against erratic shutdown (with normal applications) under ageing batteries.
In the reddit articles etc cannot see any data about folks who have had shutdowns though, where data is lost ?

As I mentioned before, it is well known that aging lithium ion batteries suffer from reduced capacity so you have to charge the phone more frequently. There doesn’t seem to be much evidence for lithium ion batteries to suffer from a reduced current supplying capability due to age. For the phone to shut off, the phone would at full speed require a certain amount of current, if the battery couldn’t supply that current, the voltage would collapse due to the current limiting. When the voltage collapses beyond a certain voltage the phone would shut down as there wouldn’t be enough volts to power the components.

Reducing the performance of the phone would reduce the current required thus solving the problem so it sounds like a good fix, as said, there doesn’t seem to be much evidence of aging batteries suffering from reduced current supplying capability. Only reduced capacity, probably why there isn’t much in the way of data for people with shut downs

UTmaniac · 22 Dec 2017 at 16:15

Apple have been admiring Nvidia's driver releases, crippling older graphics cards, encouraging users to upgrade.

Roar87 · 22 Dec 2017 at 16:18

People are still buying iPhones in this day and age?

CREATIVE!11 · 22 Dec 2017 at 16:32

Hmmmmmmmmm

Any iphone techies chime in if this is actually legit? or are they trolling and just slowing down iphones to make people upgrade.

Glad i've never bought an iphone if the latter. Screw them.

asim18 · 22 Dec 2017 at 17:39

james.miller said:
I think that's where we differ because i don't believe either is a good solution especially if it leaves a consumer in the situation where they can no longer see the screen in certain situations. figures of 100% and 50% brightness have been mentioned here but the reality is few people use their phones at 100% brightness for any real period of time. Mine for example sits mostly at 40 to 50%, so if the solution on my phone was to reduce the brightness, you're looking at (pardon the pun) a reduction to say 25-30%. that's a big difference and it stops me using the phone at all in any strong sunlight. That is not, IMO, a suitable solution for the battery issue. Neither is slowing the phone down. The answer, the only one, is a new battery. That, or design some batteries that actually last the distance and Apple are far from the only guilty party there.

The best solution is for there to simply be a notification telling you that your battery is degrading. Then it's up to the user whether he can get away with reducing brightness just a little. Then you're not forced into a situation "where they can no longer see the screen". That way you're not forced into a situation where you cant see the screen anymore. Even a small reduction in screen brightness is an advantage.

But the thing is it's even worse if they literally half the performance of your device without any warning. What if you have chargers at work, what if you're not concerned about having a battery life? The user is basically forced into halving the performance and he wont be able to play that game for 30 minutes on his commute home because it's now an unplayable jerky mess.

Therefore the "screen dimming reminder" is pretty much the best option right now. The battery savings of halving the cpu speed is still pretty much unsubstantiated.

From what I understand, there are two things which must happen in order to notice considerable battery savings from reduced cpu cycles.

A) You have to be literally bottlenecking the cpu cycles
B) The software needs to be temporally sensitive, it needs to be synced with realtime (such as video and games) and thus has a built in mechanism for compensating for no available CPU cycles, such as frame dropping.

That is to say that the frames per second in game is limited to 10fps due to bottleneck then 20 frames will be dropped and they will never be rendered, as opposed to steady 30fps with overhead available. But no one is going to play a jerky bottlenecked game anyway. All other software is not time sensitive, the commands are simply queued and the calculations will eventually be performed.

Whether it takes substantially less power to compute something in 2 seconds at 1ghz or 1 second at 2ghz hasn't really been proven here.

Six6siX · 22 Dec 2017 at 18:58

Actually, there is already a power saving mode that you have the option to activate which dims the screen and turns off background data etc when the battery gets low. Maybe it also does some CPU throttling too - I'm not sure.

Ocean Breeze · 22 Dec 2017 at 23:04

Most people’s phones slow down because they become full of crap.

I doubt you would even notice what Apple is supposedly doing. When a battery is knackered, it’s knackered. It’s not Apple’s fault that batteries degrade.

MagicBoy · 22 Dec 2017 at 23:10

Ocean Breeze said:
Most people’s phones slow down because they become full of crap.

I doubt you would even notice what Apple is supposedly doing. When a battery is knackered, it’s knackered. It’s not Apple’s fault that batteries degrade.

Did you read the OP?

Check out the Geekbench results I posted in the Apple Hardware thread from my iPhone 6. You'll notice 50%.

jpaul · 22 Dec 2017 at 23:19

Bear said:
Reducing the performance of the phone would reduce the current required thus solving the problem so it sounds like a good fix, as said, there doesn’t seem to be much evidence of aging batteries suffering from reduced current supplying capability. Only reduced capacity, probably why there isn’t much in the way of data for people with shut downs

Depending on optimistic fast charging strategies they have employed eg., the battery could exhibit unpredicatble capacity, but I tend to agree that need for rapid shutdown is unlikley,
(they probably want to conserve some capacity for those emergency calls or opportunistic selfies.)
Avoiding warranty claims on battery capacity maybe more their mark, they need to avoid excessive discharge which significantly damages potential re-charge cycles eg. see table 2

asim18 said:
Whether it takes substantially less power to compute something in 2 seconds at 1ghz or 1 second at 2ghz hasn't really been proven here

if you look at this paper
their estimate for the BigLittle architecture

As shown in Table I the A57 outperforms the A53 by almost a factor of 2 when running at the same clock speed. On the other hand the Cortex A53 consumes significantly less power, as is demonstrated in Fig. 1. It is also noteworthy that the A53 running all four cores still consumes less or equal power than only one running core of the A57 at any clock-rate.

so 2x speedup with MrBig, but same task with Mrlittle would have consumed 50% of the energy for the same task, ~~so battery is dead in half the time~~. ie could have done twice as much work with your battery charge running on MrLittle at 1GHz

MagicBoy · 22 Dec 2017 at 23:27

Six6siX said:
Actually, there is already a power saving mode that you have the option to activate which dims the screen and turns off background data etc when the battery gets low. Maybe it also does some CPU throttling too - I'm not sure.

Throttles to 62% on my iPhone 6 with a new battery.