Difference between RAM and ROM

A computer system consists of various hardware elements. The RAM and ROM are one of them. These two are different types of internal memories that have different purposes of being used in a computer.

In this article, you will learn RAM and ROM and the differences between them.

What is RAM

The RAM or Random Access Memory is used to store information temporarily which is needed by the CPU to process the current instruction or work. This information is lost when the computer is switched off.

RAM is located in the form of a hardware element on the motherboard of a computer system. An operating system also needs RAM to loads some programs when you start your system. The reason why we use RAM instead of using hard disk or any external storage device is that using RAM to read or write data is fast and easy as compared to other storage devices.

A RAM is also known as volatile memory, temporary memory, main memory, etc. The reason why we call it volatile or temporary memory is because it loses any data stored in it. When you shutdown your system or in case of an unexpected power cut.

Types of RAM

Broadly there are two types of RAM these are given below.

SRAM (Static RAM) –

SRAM stores a bit of data by using the state of a six transistor memory cell. It is faster and requires a constant power supply. SRAM is comparatively more expensive than DRAM.

DRAM (Dynamic RAM) –

DRAM stores a bit of information using a pair of transistors or capacitors. It offers reduced power consumption and costs less than SRAM. Different types of DRAM are given below.

  • ADRAM (Asynchronous Dynamic RAM)
  • SDRAM (Synchronous Dynamic RAM)
  • DDR SDRAM(Double Data Rate Synchronous Dynamic RAM)
  • RDRAM (Rambus Dynamic RAM)
  • CDRAM (Cache Dynamic RAM)

What is ROM

The ROM or Read Only Memory is a type of primary memory on a computer system that stores data permanently, even when the system is turned off. ROM is a read-only memory that means data inside the ROM can be read but it cannot be written on it.

The data or programs in ROM are filled by the manufacturer in such a way it cannot be reprogrammed or rewritten. The program stored on ROM is important for the functioning of a computer or some other electronic device. Some kinds of ROM allow modifying data stored on them.

Types of ROM

Some important types of ROM are –

  • PROM (Programmable ROM) – This type of ROM can be programmed only once after the creation. It is not erasable that means programmed once cannot be erased.
  • EPROM (Erasable Programmable ROM ) – The data inside this type of ROM can be erased by exposing it to high-intensity UV light for a certain period of time.
  • EEPROM (Electrically Erasable Programmable ROM ) – The data on this type of ROM can be erased electrically. It can be erased and reprogrammed multiple times.
  • Mask ROM – In this type of ROM data is written while the manufacturing of the chip

RAM vs ROM: The key differences

Some key differences between RAM and ROM are given in the table below.

It is volatile memory that means data on the memory exist as long as the power is suppliedIt is a non volatile memory that stores data permanently it does not affected by the power supply
Data inside the RAM can be retrieved and alteredThis is read only type memory that mean can not alter its data
Speed of RAM is much faster than the ROMThe ROM is slower as compared to RAM
It is necessary to run an application quicklyIt stores the data or programs that are essential for system boot process
Physically the RAM is larger in size and have higher storage capacityComparatively it smaller in size and have less capacity
RAM is more expensiveIt is cheaper than RAM
It is used as CPU cache or primary memory in a computerIt is used as firmware by micro controllers
Electricity is require to preserve the infromationThe information inside the ROM is preserved even if there is no electric supply


Here you have seen the differences between RAM and ROM. I hope the information given here is useful to you. Now if you have any query then write us in the comments below.

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