A processor (CPU) is the logic circuitry that responds to and processes the basic instructions that drive a computer. The CPU is seen as the main and most crucial integrated circuitry (IC) chip in a computer, as it is responsible for interpreting most computer's commands. CPUs will perform most basic arithmetic, logic and I/O operations, as well as allocate commands for other chips and components running on a computer. The term processor is used interchangeably with the term central processing unit (CPU), although strictly speaking, the CPU is not the only processor in a computer. The GPU (graphics processing unit) is the most notable example, but the hard drive and other devices within a computer also perform some processing independently. Nevertheless, the term processor is generally understood to mean the CPU.Processors can be found on PCs, smartphones, tablets and other computers. The two main competitors in the processor market are Intel and AMD.