It was off by default, but it turns on if your phone unexpectedly shuts down. They later added the option to turn it off.
The thing is, they were covering up a battery defect unique to a few models like the iPhone 6. Also the throttling was pretty conservative. It made my phone lag so hard that even typing in a default app like Messages was a chore. My phone almost never shut down even after I disabled it, so it's not like I needed it.
> The thing is, they were covering up a battery defect unique to a few models like the iPhone 6.
Do you have any proof of this?
> My phone almost never shut down even after I disabled it, so it's not like I needed it.
“Almost never” sounds like you did. There are a few factors at play such as temperature that can’t be exactly characterised so it has to be conservative.
Mine shut down once, at a low %. It was a very easy decision to disable the throttling. Even if I were unlucky enough to get a model that shut down more frequently, the throttling was so bad that it'd have been worth disabling.
I don’t see any indication this feature was put there to cover up the issue. It would definitely help since it helps with battery degradation in general, but they would limit it to specific models if it was that targeted and there would be no need to still have the feature around today.
"For iPhone 6, iPhone 6 Plus, iPhone 6s, iPhone 6s Plus, iPhone SE (1st generation), iPhone 7, and iPhone 7 Plus, iOS dynamically manages performance peaks to prevent the device from unexpectedly shutting down, so you can still use your iPhone."
It was limited to certain models, which makes sense because personally, I've never seen an older iPhone (≤5) shut off randomly. Apple didn't say what the affected models have in common.
The feature still exists today. On my iPhone 11 I can go in to the settings under Battery -> Battery Health & Charging and see that I have “Peak Performance Capability”.
This isn’t an issue unique to iPhones either. Different battery chemistries will behave differently and different technology nodes and designs will have varying supply requirements, but in general the internal resistance will increase as the battery ages and cause brownouts as the voltage dips under high load.
It's called something similar, but it doesn't seem like the same thing. For one, I don't think you can force an iPhone 11 into max performance mode like you can with a 6. If you read the context around that quote on Apple's site, the later phones are called out separately.
I understand that batteries in general can have voltage dips as they degrade, but the 6-7 had something especially wrong with them. Unlike Antennagate, Batterygate was a real thing.
They are broadly the same. It’s a bit more dynamic now rather than on/off but still throttling based on battery health. They are probably monitoring the rails and clocking down directly on a feedback loop which is the way to do it if you want to eke out all the performance you can.
11 and above:
> While performance impacts are reduced as much as possible, battery ageing might still eventually lead to noticeable, possibly temporary, effects. Depending on the battery state, level of charge and the tasks that your iPhone is handling, examples might include longer app launch times, lower frame rates, increased processing times, reduced wireless-data throughput, backlight dimming or lower speaker volume. During the most extreme cases, the camera flash or other camera features might be temporarily disabled.
> Additionally, you can see if the performance-management feature, which dynamically manages maximum performance to prevent unexpected shutdowns, is on, and you can choose to turn it off. This feature is enabled only after an unexpected shutdown first occurs on a device with a battery that has diminished ability to deliver maximum instantaneous power. This feature applies to iPhone 6, iPhone 6 Plus, iPhone 6s, iPhone 6s Plus, iPhone SE (1st generation), iPhone 7 and iPhone 7 Plus. Starting with iOS 12.1, iPhone 8, iPhone 8 Plus and iPhone X include this feature; iPhone XS, iPhone XS Max and iPhone XR include this feature starting with iOS 13.1.
As far as I know they added a setting to turn that feature off. Not sure if that's on by default or not.