Monday, December 11, 2017

Does iOS Throttle CPUs When Using a Degraded Battery?

Tim Hardwick (Hacker News):

A Reddit post over the weekend has drawn a flurry of interest after an iPhone 6s owner reported that a battery replacement significantly increased the device’s performance running iOS 11. The ensuing discussion thread, also picked up by readers in the MacRumors forum, has led to speculation that Apple intentionally slows down older phones to retain a full day’s charge if the battery has degraded over time.

According to TeckFire, the author of the original Reddit post, their iPhone had been very slow after updating to iOS 11, especially compared to their brother’s iPhone 6 Plus, so they decided to do some research with GeekBench and battery life apps, and ended up replacing the battery.

Just over a year ago, Apple launched a repair program for iPhone 6s owners after some users reported their devices were unexpectedly shutting down. Apple said the problem was down to a manufacturing issue affecting a “very small” number of iPhone 6s devices, and offered battery replacements free of charge to owners of devices within a limited serial number range.

Chance Miller:

Some in the thread speculate that Apple was inundated with battery replacement requests because of the random shutdown issue, and instead of coming clean about it, throttled devices with a software update to “solve” the problem[…]


If you feel that you’re affected by this problem, you can use an app like CpuDasherX to see your device’s clock speed. Users report that the clock speed shown here is less than what it should be, adding merit to suggestions that Apple throttles devices affected by the shutdown issue.

While Apple says that Low Power Mode can reduce device speed in an effort to save battery life, this appears to be completely different and affects users without that featured enabled.

Matt Birchler:

But if this is indeed legit, I honestly don’t think it’s a bad decision by Apple. If your phone has a worn out battery and the system has to choose whether to make your phone last longer or run faster, I think making it run a little slower so that it doesn’t die is the right call. It’s essentially doing what Low Power Mode does already, just without your need to toggle it on or off.

That would make sense—and also vindicate all the people who were dismissed (including by me) for complaining about iOS updates intentionally slowing down their phones. But Apple should be up-front about doing this and about which iPhones are affected.

Previously: Do iPhones Get Slower Over Time?, iOS 10.2.1 Update Reduces Unexpected Shutdowns, Apple’s Support Gap.

Update (2017-12-18): John Poole:

First, it appears the problem is widespread, and will only get worse as phones (and their batteries) continue to age. See, for example, the difference between the distribution of iPhone 6s scores between 10.2.1 and 11.2.0.

Second, the problem is due, in part, to a change in iOS. The difference between 10.2.0 and 10.2.1 is too abrupt to be just a function of battery condition. I believe (as do others) that Apple introduced a change to limit performance when battery condition decreases past a certain point.


Users expect either full performance, or reduced performance with a notification that their phone is in low-power mode. This fix creates a third, unexpected state. While this state is created to mask a deficiency in battery power, users may believe that the slow down is due to CPU performance, instead of battery performance, which is triggering an Apple introduced CPU slow-down. This fix will also cause users to think, “my phone is slow so I should replace it” not, “my phone is slow so I should replace its battery”. This will likely feed into the “planned obsolecense” narrative.

See also: Paul Haddad.

Update (2017-12-19): Bob Burrough:

If this is confirmed (the data sure looks compelling), I don’t think this is a defensible decision. People expect batteries to deteriorate. They don’t expect CPU’s to deteriorate. If the CPU were left alone, it just means your battery would die sooner. That’s a service call...

Just head into any Apple store (etc), they’ll replace the battery, and you’re good as new. However, if you’re feeling that your phone is just slow, there is no service call for that. Only a new phone would help.

Also, there’s no reason not to display a dialog that says “Your battery has reached the end of its usable life, please bring your iPhone to the nearest Apple store for a replacement.”

Zac Cichy:

This is really damning if it turns out to be the case. Hesitant to comment much further....

But. If true, this demonstrates an Apple that is transforming into everything their harshest critics say. Planned obsolescence!?!

See also: Hacker News.

I still think slowing down the phone to save battery makes sense for most users. But iOS should say that it’s doing this so that the user can get the battery replaced. In other words, help the customer fix the root problem rather than papering over it. Many of these phones are still under AppleCare. Secondly, it seems like enough phones are affected that either there’s something wrong with the batteries or the phones were not designed with enough battery capacity.

Update (2017-12-20): Zac Cichy:

It should be possible to opt-out. And Apple ought to be able to give users some kind of warning when battery degrades past a certain point, with an option to service the device.

But again, they are not incentivized to do that.

Except that it will really hurt Apple’s reputation when customers find out they’ve been deceived.

8 Comments RSS · Twitter

Agreed entirely with your take, @mjtsai.

It'd be nice to have a battery health check feature in Settings to inform the user of what's going on with their battery and phone performance.

Since they've hidden this away like they have, if this gets picked up by mainstream news outlets, I'd expect brand-damaging repercussions to be part of the fallout.

And the fact that phone manufacturers have made phone batteries non-user-replaceable makes this even worse, IMO.

Second Thought: Imagine this behavior in something like an Apple Car.

If true, this is quite insane.

Low Power Mode is a user decision. If Apple is doing this without giving users an option, sheerly to keep it covert, that's massively screwed up, IMHO.

Sander van Dragt

Of a car had a problem and runs at half Power, there would be a red engine light. Why does iOS not notify the user that their cpu is throttled and their battery needs replacing? Bad communication makes this come across slightly disingenuous.

1. The reported issues is not iPhone 6s only? but also on iPhone 6 and 7

2. The CPU uses roughly 20% of the energy usage, compared to Network connections and Display. I dont see why this is a good solution.

3. Apple has a high financial incentive to do this.

4. It happens on Mac as well

And no one is complaining? This, if turns out to be true, is absolutely insane and downright unethical.

>I still think slowing down the phone to save battery makes sense for most users.

I disagree. People are already used to bad battery life. iPhones don't last through a day for many people even when they're new. Everybody has mitigation strategies for that problem. Battery problems are a normal fact of life when you're using an iPhone.

Performance problems, on the other hand, are not. iPhones perform well, and people expect them to. So Apple is attempting to solve a problem people have already solved, by creating a problem people hadn't had previously.

Furthermore, unlike with poor battery life, if your game suddenly doesn't run well anymore, there's no mitigation strategy available to you. You can't carry an external battery pack to fix this problem. So not only is Apple creating a new problem, it's creating a problem that can't be solved at all.

Also, like Ed points out, the throttling the CPU isn't even going to improve battery life in a way that is noticeable to most people.

And all of this ignores the point that Apple is validating the worst anti-Apple conspiracy theories. How utterly devoid of any kind of logical thinking skills do you have to be to commit to such a braindead action? This alone makes me wonder if there's something happening here that we're missing.

This is utterly insane behavior on Apple's part. Of all the crap they've pulled in recent years, this takes the absolute cake, and makes it obvious that Apple's leadership is either just unfathomably incompetent, or intentionally acting against the interests of its own users, under the assumption that they're too dumb to notice.

This whole story is just completely off all charts. I almost can't believe Apple is dumb enough to do something like this.

>It happens on Mac as well


[…] of shutting down? If so, that would explain why Apple didn’t provide a way for users to opt in. What use is it to opt into making your phone crash? But I’m not sure this matches up with […]

Adrian Bengtson

> I disagree. People are already used to bad battery life.

Bad battery life is one thing, unexpected shutdowns because of cold weather is another. I rather have a slow working phone than a dead one.

(But as other have said many times; most of all I'd like to know that replacing the battery solves the problem. I did replace it and all my issues were gone.)

Leave a Comment