iPhone XS Max 20% battery reduced speeds

jjk454ss

macrumors 601
Original poster
Jul 10, 2008
4,337
440
Does iOS slow down/throttle the iPhone speeds when you hit 20% battery, even without turning on low power mode? I swear things get slower even on my XS Max once it hits 20% battery, even though I do not turn on low power mode.
 

internetrando

macrumors 6502
Jun 5, 2018
426
244
Texas
Does iOS slow down/throttle the iPhone speeds when you hit 20% battery, even without turning on low power mode? I swear things get slower even on my XS Max once it hits 20% battery, even though I do not turn on low power mode.
Unless you turn on low power mode, nothing should change.
 

TooMuchChocolate

macrumors newbie
Apr 5, 2019
24
18
I have actually experienced something like this. My phone (SE) had a problematic battery, and when it reached a low charge level it became unusably slow. It was on that reduced performance/throttle mode, but I always thought that worked something like:

Phone detects battery problem -> phone steps from one set of fixed clock speeds to a lower set of fixed clock speeds and stays there -> phone is the same amount slower whether you are at 100% charge or 5% charge.

But the above experience made me wonder if the throttling is dynamic, so that the phone is, say, actually running lower clocks (throttling more) at 5% charge than it is at 100% charge. Does anyone know if that's correct?
 

jjk454ss

macrumors 601
Original poster
Jul 10, 2008
4,337
440
I didn’t think it was supposed to change, but especially in a game it sure appears to slow down. Maybe it’s on my head, but I sure do to think it is;(. It’s when it hits the “red” below:

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