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iOS is throttling cpu when battery level drops below a certain percentage

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chillip

macrumors 68040
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Mods, please note that this is a totally separate issue to the other thread. So please do not merge this.

I believe that iOS throttles cpu when battery drops below a certain level and here is my evidence.
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The benchmark taken at 06:05 was when the battery was at 100% and the one taken at 11:10 was battery at 43%. You can see a massive difference in the score.

Also note the battery levels and cpu frequency on the screen shots from CPUDasher X. Clearly shows throttling in action.

I must stress again that this is totally separate from the battery wear thread. This is purely based on battery % level. It would be good to see other Geekbench results from various phones at different battery levels. Mine is an iPhone 7.

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chillip said:
This is a different issue! Read my post!
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Because that other thread is regarding battery health as the battery ages, my issue is with battery level.
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sounds the same. they both involve the battery.
 
Yes but the other one is to do with the ages of the battery. This is to do with when the charge drops below say 50% and iOS throttles the cpu. Totally different.
 
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Why would i get normal bench mark at 100% and then much lower at 43%. Battery is 6 months old. I believe cpu is throttled when charge drops below 50% not matter how old battery is.
 
chillip said:
It’s almost like iOS is forcing low power mode when battery level drops.
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Not quite low power mode (which disables a bunch of other features) but certainly seems like CPU throttling.

Logically, the CPU should actually be throttled (or using the low power/high efficiency cores) majority of the time. The CPU certainly doesn't need to be running full speed when checking email, listening to music, reading books, watching videos, etc. The unusual thing is that iOS 11 now seems to be capping peak performance based on battery charge level per your screenshots.
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chillip said:
Would be good if anyone else can test my claims
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Can't test with devices on-hand at the moment. My iPhone 7 is still on iOS 10.3.3. However, the iPhone 5s which is on iOS 11.2 doesn't appear to have this issue.

I could check later with my mom's SE which is also on iOS 11.2.
 
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