The A7 is newer and more powerful than the A6, particularly because it’s a 64-bit chip (the first in a smartphone). Because it’s 64-bit, the A7 can process chunks of data twice as big as those handled by the 32-bit A6. Processor speed isn’t as big a factor in smartphones as it is in computers (many other things affect overall performance as much as, if not more​ than, processor speed), and the A6 is fast, but the A7 in the iPhone 5S makes that model speedier than the 5C. This includes much more detailed fitness and exercise data in apps, and the ability to know whether the user is sitting or standing. The 5S has it, but the 5C does not. This scanner lets you tie the security of your iPhone to your unique, personal fingerprint, which means that unless it’s you (or someone has your finger!), your phone is very secure. Set up a passcode and then use the fingerprint scanner to unlock your phone, enter passwords, and authorize purchases. The scanner is available on the 5S, but not the 5C. But the subtle details of the 5S’s camera really stand out. It offers two flashes for true-to-life colors, the ability to record slow-motion video at 120 frames per second in 720p HD, and a burst mode that takes up to 10 photos per second. The 5C’s camera is good, but it doesn’t have any of these advanced features. The iPhone 5S has more colors than previous models — in addition to the standard slate and gray, it now also has a gold option — but the 5C has the brightest colors and the biggest selection of them. The 5C matches the 16 GB and 32 GB models that the 5S offers, but it stops there — there’s no 64 GB 5C for storage-hungry users.