Why iOS 11 runs slow and drains your iPhone’s battery [EXPLAINED]

As you already know, iOS 11 slows down a lot of devices and we are yet to get a fix for this problem. Here’s the reason behind the stark performance decrease older devices experience on iOS 11.

iOS 11 is designed for neural A11 Bionic chips

iPhone 8, 8 plus, and iPhone X come with the ultra-powerful A11 Bionic processor, which is the first iPhone chip ever to come with integrated AI.

The “bionic” class of chips allow the operating system to work in a much better and efficient manner.

The advantages of an AI-first device are enormous and translate directly into low power consumption and faster processing.

A11 Bionic processor

Apple designed iOS 11 specifically for its modern devices with these processors.

The internal structure of Apple’s latest operating system makes extensive use of the neural engine. The older processors such as the A10 and A9 don’t have the neural engine.

Moreover, their processing power is nowhere close to the A11, which further degrades their performance.

Therefore, we notice a significant performance decrease in older models.

Is this planned obsolescence?

Yes, it certainly is. Apple wants users to buy their latest smartphones by deliberately implementing such a major performance decrease.

Apple actually had two options in front of them –

  • Create two different versions of operating system, each of which caters to modern and older processors respectively.
  • Create a single version of operating system and run AI-based processes in emulation mode on older processors.          

iphone x

Apple went with the latter, which indicates why the slowdowns occur.

All AI-based processes exert older processors even further in order to extract the same level performance as in older devices. This leads to battery loss and slight delays.

How can I increase performance on iOS 11?

1. Raise VNODE limit

Raising VNODE limit on iOS often speeds up performance and makes it more stable. However, you can do this only if you are running a jailbreak.

This technique involves manually increasing the cache size over the stock limit. This results in superior performance without any slowdowns.


I am yet to test it on my device but won’t think twice about it if I experience major slowdowns.

2. Downgrade from iOS 11 to iOS 10

iOS 10 is optimized for older models, especially iPhone 5s, and is butter smooth on pretty much all 64-bit devices.

Therefore, downgrading from iOS 11 to iOS 10 is your best bet right now. However, this downgrade process works only with A7 devices.

You can read this tutorial for downgrading iOS 11 to 10.3.3 or below on A7 models.


If you own a device with an A8 or newer chip, you can’t go back to iOS 10. You are out of luck even if you have SHSH Blobs for iOS 10.3.3.

3. Wait for an update

If you are not into jailbreaking and iOS enthusiast stuff, you must wait for an iOS update. There’s no method whatsoever to increase performance without a jailbreak.

You can only hope Apple develops a better iOS update in the coming months and pushed it out as soon as possible.

ios firmware

If you want to minimize battery drain, I highly recommend turning off your location services.

If you have any other trick or method for increasing the performance of your iPhone, don’t forget to share it below.

For more iOS and firmware news, give us a thumbs up on Twitter and Facebook.

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