iPhone 7 has an A10 Fusion processor. What does this mean?

Apple's A10 Fusion features 4-core architecture, providing speeds 2x faster than the iPhone 6.

Two cores are high-performance cores. The other two are low-power cores, which sip just 20% of the power consumed by the high-performance cores. An intelligent controller can save significant battery life by directing simple tasks to the low-power cores.

The A10 comes with graphics 3x faster than the iPhone 6. Also included in the system is the M10 motion coprocessor and a new image signal processor (ISP) to work with data from the camera. in addition to speed, improvements in the A10 result in two hours of additional battery life on the iPhone 7 and an extra hour on the iPhone 7 Plus.