A processor is an integrated electronic circuit that performs the calculations that run a computer. A processor performs arithmetical, logical, input/output (I/O), and other basic instructions that are passed from an operating system (OS). Most other processes are dependent on the operations of a processor. A processor, also called a central processing unit (CPU), is the main chip in a computer that carries out the instructions of a computer program. It performs the basic arithmetic, logic, controlling, and input/output operations specified by the instructions. Intel, AMD, Qualcomm, Apple, and Samsung are the best processor brands.