What is CPU (Central Processing Unit)?

CPU stands for Central Processing Unit also called a central processor, or just processor is an electronic circuit that follows the instructions from a computer program. The CPU performs basic logic, arithmetic, controlling, and input/output operations as defined by the instructions in the program.

It runs applications and operating systems while receiving input from the user or program. It performs multiple operations such as store data, process data, and output results.

The CPU has at least one processor that is the actual chip inside the CPU that does the calculations. For many years most CPUs only had a processor, but in latest CPU models have more than one processor cores.

A CPU with two processing chips or cores is called a dual-core and a CPU with four cores is called a quad-core.

High-end CPUs can have six (Hexa-core) or eight (octa-core) processors. A computer can have two or more CPUs, each with multiple cores.

For example, a server with three (dual-core) CPUs has a total of 6 processors.

What does the CPU do?

The CPU’s primary function is to take input from computer programs and peripheral devices (mouse, keyboard, printer, etc.) and interpret what is needed. The CPU then either provides information to your monitor or performs peripheral requests.

Components of CPU

Components of the CPU:

There are three primary components of CPU:

  • Memory or Storage unit
  • Control Unit
  • ALU (Arithmetic Logic Unit)

Memory or Storage Unit:

This unit can store instructions, data, and intermediate results and provides the information to other computer units when needed. Primary memory and secondary memory are two types of memories in a computer. Its size affects power, capacity, and speed.

Functions of the memory units are:

  • Stores all the necessary data for processing.
  • Stores the intermediate output of the processing.
  • All results and output are transmitted through the main memory.
  • Stores the processing output before displaying the results on the output devices.

Control Unit (CU):

The control unit manages all the operations of all parts of the computer but does not process the data

The responsibilities of the control unit include:

  • It is responsible for transmitting and controlling instructions among other units in the computer.
  • It coordinates and manages all the other units of the computer.
  • It receives instructions from memory, acts on them, and sends the output to the computer.
  • It interacts with input or output devices to transfer the data from storage.


ALU stands for Arithmetic Logic Unit. This is the third and final component of the CPU.

It consists of two sub-sections:

  • Arithmetic unit
  • Logical unit

1. Arithmetic unit:

The function of the arithmetic unit is to perform mathematical operations such as subtraction, addition, division, and multiplication. All complex operations are performed using the above operations repeatedly.

2. Logical unit:

The logical unit is responsible for performing logical operations such as data selection, matching, comparison, and merging.

How fast does the CPU transfer data?

Like any device that uses electrical signals, the data travels very close to the speed of light, which is 299,792,458 m / s. 

How close a signal can be received at the speed of light depends on the medium through which it travels. Most of the electrical signals travel at 75 to 90 percent of the speed of light.

Difference between CPU and GPU?

The difference between CPU and GPU is that CPU is designed to handle a huge range of tasks faster and GPU has been developed to quickly load the high-resolution videos and images simultaneously.

Can a GPU be used instead of a CPU?

No, Although GPUs can perform many functions like CPUs, they cannot perform the required functions that some software and operating systems need.

Can a computer work without a CPU?

No. All computers need some kind of CPU.

Features in CPU:

The CPU consists of the following features.

  • The CPU handles all types of data processing.
  • It manages and controls all the parts of the computer.
  • It stores data, programs (instructions), and results (output).


Processors can have multiple sizes and levels of caches that improve CPU performance. For the processing and execution of instructions, the CPU plays an important role in a computer system with its various components.