A new feature in iOS 9 could give users up to three hours more of battery life. The low power mode feature is coming to iOS 9 upon its release and it is expected to cut down the performance of the iPhone in order to offer more power, PC Magazine reports.

According to Mac Rumors, by cutting the performance of the iPhone, the battery can be stretched for a few hours more. The cuts mean slower performance and disabling some features.

Users will notice about a 40 percent decrease in the iPhone's performance. The decrease in performance will not be a huge difference for casual users who are just checking e-mails or performing light web browsing. However, anyone who tries to game on their iPhone while in low power mode will probably be disappointed. The low power mode has not been tested on apps yet.

When tested, the low power mode does affect the performance scores that an iPhone receives. Mac Rumors was able to use the Geekbench 3 app to determine the performance of an iPhone running in low power mode.

Low power mode will automatically kick in when an iPhone hits the 10 or 20 percent battery mark. The iPhone will be affected in other ways too.

"Low Power Mode temporarily reduces power consumption until you can fully charge your iPhone. When this is on, mail fetch, background app refresh, automatic downloads, and some visual effects are reduced or disabled," the description for the latest iOS 9 beta reads.

According to MacWorld, the best way to save battery used to be shutting off WiFi, disabling Bluetooth, turning off LTE data or even putting the phone into airplane mode. With the low power mode, users will be able to keep all of these settings on and still save on battery. Background mail fetching and app refreshing will stop while in the mode and animated wallpapers will stop moving.