A7 and 64-bit
iPhone 5s is powered by Apple’s next generation A7 chip, making it the world’s first smartphone with 64-bit desktop-class architecture for blazing fast performance in the palm of your hand. The iOS kernel, libraries, and drivers now take advantage of 64-bit, delivering up to 2x faster CPU and graphics performance for your apps and games. And it’s easy to build and run your apps in 64-bit because Xcode automatically builds your apps into binaries that will run on both 32-bit and 64-bit devices.