To extend battery life at the cost of speed or not extend battery life? That is the question.
We learned earlier this month that iOS 9 will give your iPhone one extra hour of battery life, and a "Low Power Mode" will give you up to three more hours. In exchange for that extended battery life, though, your iPhone will throttle performance, according to testing done by MacRumors.
The Apple-focused blog ran Geekbench 3, a benchmark test that measures a device's processor power, on an iPhone 6 Plus and iPhone 5S. It discovered the single-core and multi-core scores for their processors dropped by about 40% with iOS 9's Low Power Mode turned on.
Low Power Mode conserves power by switching the Mail app to manual fetch, disabling background app refresh and downloads, reducing motion and brightness, and reducing network speed. A significant performance reduction isn't mentioned on Apple's website.
Apple is not alone in throttling performance in order to achieve longer battery life. As part of the release's Project Volta improvements, Android 5.0 Lollipop's built-in battery saver mode also does something similar to eke out more power.
The benchmarks are quantitative indicators that your iPhone will become almost half as fast, but we'll have to see what that actually translates to. I'm willing to bet you'll still be able to browse the web, send text messages and tweet without seeing any huge performance dips. For example, using an iPhone 6 may be similar to using an iPhone 5.