With the release of iOS 12.1 performance management function appeared on the iPhone 8, Plus 8, and X. It allows you to turn off the CPU and slowing improve smartphone performance. Previously, such a possibility was present only on the iPhone 6, 6 Plus, 6s, 6s Plus, 7, 7 Plus and SE.
earlier Apple Support page It reads as follows:
With enhanced hardware and software iPhone 8 and later, you can more accurately estimate battery capacity and power requirements of the device, which increases the overall performance system. Thus, performance management on iOS done in a new way that lets you identify more precisely the threat of unexpected shutdown and to prevent it. As a result, work performance management functions on iPhone 8 and later models may be less noticeable. Over time, the battery capacity and peak performance on any iPhone or reduced, and therefore the need to replace the battery.
But after the release iOS 12.1 The following information appeared on this page:
Starting with iOS 12.1, performance management functionality is available on the iPhone 8, iPhone 8 Plus and iPhone X, but them her work may be less noticeable in view of the advanced hardware and software software.
performance management function does not allow to disable deceleration processor without prejudice battery: Its aging will be faster. On the other hand, you can leave the start delay: so the smartphone will be longer to brake, but the battery will last longer.
To find the function, go to "Battery" in the settings, and then click "Battery status". There, under the item "Peak Performance" will "Disable" button, but only if the battery can not provide the peak power.
Recently, the Italian Competition Authority has fined Apple € 5 million. The reason was that the company has slowed the work of smart phones, without informing the user and without giving them to revert to an older version of the operating system in which the above functions not.