The central processing unit (CPU) is a lot like the "brain" of a device. It handles all of the necessary calculations to run the operating system and all of your applications.

Although CPUs can vary greatly in size, it's generally fairly easy to identify them. Most devices have a heatsink (see previous step) keeping the CPU cool. Find the heatsink, and you'll generally find the CPU hiding underneath.

Be careful when removing CPUs, because they can be very delicate. Additionally, some CPUs (Apple's A7 for example) can't be removed because they are soldered into the motherboard. If a CPU doesn't come off easily, do NOT try to desolder it, as you might cause irreparable damage to it.