Clock Speed

Clock speed is one of the most important features of a microprocessor. A microprocessor is basically the brain of the computer. We can also call it simply a processor or CPU. Furthermore, a microprocessor is basically a computer processor that is mounted on a single IC (Integrated Circuit). It means that all the functions of the processor are included on a single chip. Furthermore, the basic task of a microprocessor is to input the instructions from the memory, decode, and process them and produce the output.

The speed at which a microprocessor can execute the instructions is called the clock speed. Basically clock speed is the number of cycles that the processor executes per second. We measure it in MHz(MegaHertz) or GHz (Giga Hertz). Here, MHz means 1 million cycles per second and GHz means 1 billion cycles per second. Moreover, a cycle basically means a single electric cycle.  Besides, every microprocessor has an internal clock that regulates the speed at which it executes the instructions.

Effect of Clock Speed on the Performance of Microprocessor

We consider the clock speed as the measure of computer power’. But,  this may not be true n all cases. It means that the clock speed is not always proportional to the performance level. For example, if you double the clock speed keeping all the other components unchanged, the performance will not necessarily become twice.

Some microprocessors may perform just one instruction per cycle, whereas the others may perform multiple instructions per cycle. Hence, the second one will perform better. Moreover, other factors and components also play an important role. For example the bus speed, a 32-bit bus will perform faster in comparison to a 16-bit bus at a given clock speed.

Only increasing the speed may not result in better performance. Moreover, a very high clock speed can damage the chip also due to heat.

Clock Speed of Different Microprocessor

There may be different types of microprocessors like 16-bit, 32-bit, etc. All of them vary in terms of speed. Examples are as follows:

16-bit Microprocessor

  • 8086 microprocessor: 4.7MHz, 8MHz, 10MHz
  • 8088 microprocessor: more than 5MHz
  • 80186/80188 microprocessor: 6MHz
  • 80286 microprocessor: 8MHz

32-bit Microprocessor

  • INTEL 80386: 16MHz to 33MHz
  • INTEL 80486: 16MHz to 100MHz
  • PENTIUM: 66MHz

64-bit Microprocessor

  • INTEL CORE-2: 1.2GHz to 3 GHz
  • INTELi7: 66GHz to 3.33GHz
  • INTEL i5: 2.4GHz to 3.6GHz
  • INTEL i3: 2.93GHz to 3.33GHz

Other Important Characteristics of Microprocessor

There are three important characteristics of a microprocessor. They are as follows:

  • Clock Speed
  • Word Size
  • Instruction Set

Word Size

It is the number of bits that a processor can process in a single instruction. Furthermore, the word size decides the amount of RAM that the processor can access at a time. Moreover, it also decides the number of input and output pins on the microprocessor. These pins in to decide the architecture of the processor.

The number of input and output pins is always equal. For example, the first commercial processor Intel 4004 was a 4-bit processor. hence, it has 4 input/output pins. Today, mostly 32-bit or 64-bit are used.

Instruction Set

An instruction is basically a command which tells the computer to operate on some piece of data. The set of machine-level instructions that a microprocessor executes is the instruction set. The operations involved in the instructions can be as follows:

  • Arithmetic operations
  • Logical operations
  • Data transfer
  • Input/output operations
  • control flow

Parts of a Microprocessor

The basic parts of a microprocessor are as follows:

  • CPU
  • Bus
  • Memory

CPU (Central Processing Unit)

This is a really important part of a computer as it performs all the processing parts of the computer. It processes the data and instructions which the user gives. Moreover, it carries out the calculations and other such tasks. Other names of CPU are Central Processor or Main Processor.  It has the following parts:

1. Arithmetic and Logical Unit

As the name suggests, this unit is responsible for performing arithmetic tasks like addition, subtraction, multiplication, division moreover, it also makes logical decisions like greater than less than, etc. And hence the name, the ‘brain’ of the computer.

2. Control Unit

This unit is responsible for looking after all the processing. It organizes and manages the execution of tasks of the CPU.

3. Registers

These are memory areas which the CPU directly uses for processing. So, it’s function is to store data from input or store data between calculations. Besides, it also stores the output results. Moreover, accessing registers is much faster than accessing the RAM.

4. Decoder

It decodes the instructions from high-level language to machine language and passes them to the CPU.

5. Instruction Register (IR)

It stores the instruction which will execute currently.


The functional components usually use a bus architecture for communication. A bus is a collection of wires used for the communication of different parts of a computer. Further, it uses electric signals to pass the data and information.

Bus Architecture
Bus Architecture

Different Types of Buses used are:

1. Address Bus

The address bus is used to communicate the address of the given data and instructions.

2.Data Bus

The data bus is used to communicate the data from one part to another.

3. Control Bus

The control bus is used to control the signals between different devices. Therefore, in conclusion, we can say that these functional components communicate through this bus architecture. The input device takes the input, then the data is processed and the output devices display the results. Besides, the system bus performs all the communication that the cycle involves.


The parts of memory are:

Primary Memory

This is the internal memory that stores the data and instructions of the CPU. It is volatile in nature (data is lost when the power is disconnected).

The primary memory has two types:

  1. RAM (Random Access Memory)

As per the name, data can be accessed randomly and quickly.

  1. ROM (Read Only Memory)

As per the name, we can only read data and cannot write (store) to it.

Secondary Memory

As we know that the primary memory is volatile therefore, we need some devices to store the data permanently so we use some external storage devices for this purpose which we name as the secondary memory. Some examples: CD, DVD, etc.

Frequently Asked Questions (FAQs)

Q1. What is clock speed?

A1. The speed at which a microprocessor can execute the instructions is called the clock speed. Basically clock speed is the number of cycles that the processor executes per second.

Q2. What is the unit for measuring the clock speed?

A2. We measure it in MHz(MegaHertz) or GHz (Giga Hertz).

Q3. Does the clock speed directly affect the performance of a microprocessor?

A3. No, it is not necessary that if the clock speed increases then the performance also increases. Moreover, it depends on other hardware components also.

Read More

error: Content is protected !!