Apple received a number of lawsuits when the public found out the company purposely, and knowingly slowed down iPhones when the battery degraded to a level that it couldn’t keep up. As a result, Apple throttled the iPhone to extend the battery life, but this resulted in a bad user experience as the performance became choppy and slow.
Chinese users are reporting that changing the iPhone’s geographical location to France can improve the performance of the device.
The reason why changing the region to France may help, might be explained by the heavy fine that the government issued Apple with when the battery-gate fiasco came to light. France didn’t let this slip and demanded the company to fix the issues. As a result, the infamous “Performance management” system is deactivated when the region is changed, and that’s why the performance improves, at times, significantly on older iPhones. Here’s a benchmark of the before and after when changing regions (via PhoneArena).
Newer iPhones don’t seem to have a similar effect, and virtually there is no difference between changing regions. It remains to be seen if that’ll change after the latest devices have older batteries, but it’s unlikely to make any significant change.
It’s important to keep in mind that while what Apple did was wrong, batteries are consumable products and will eventually need replacing in almost all products that use them on a regular basis, and even if it’s rarely used. Batteries are meant to be replaced, used and recharged. Having 80-85% battery health after one year of use with a newly purchased device is considered normal, according to Apple. If you have a recent device that supports the “Performance management” option in the system and you want to improve your performance, you can toggle it off, or on, since Apple was forced to include this option on newer, and on older devices.