The Processor The processor is the part of the computer that does the computing. Basically it is the command center. Everything goes through it and it sends out commands. It performs arithmetic and logic operations. The processor follows the instructions given to it by the programs. Processors are usually large squares that are found on the motherboard. Below are two different brands of processors made by AMD(left) and Intel (right). Below the two pictures is the slot on the mother board where the processor is placed.