What is RAM?

The full form of RAM is Random Access Memory. The information stored in this type of memory is lost when the power supply to the PC or laptop is switched off. The information stored in RAM can be checked with the help of BIOS. It is generally known as the main memory, or temporary memory or cache memory or volatile memory of the computer system.

In this RAM vs. ROM tutorial, you will learn:

What is ROM?

The full form of ROM is a Read-Only Memory. It is a permanent type of memory. Its content are not lost when the power supply is switched off. The computer manufacturer decides the information of ROM, and it is permanently stored at the time of manufacturing, which cannot be overwritten by the user.


  • RAM stands for Random Access Memory while ROM stands for Read-Only Memory
  • Data stored in Random Access Memory popularly known by acronym RAM stays there until the computer is running whereas Read Only Memory popularly known by acronym ROM is used mainly in the start-up process of a modern computer
  • Important RAM types are 1) DRAM 2)SRAM. SDRAM, and DDR and Important ROM types are 1) EPROM 2) EEPROM, 3) PROM, and 4) Mask ROM,
  • RAM is volatile whereas ROM is non-volatile Memory
  • The biggest advantage of RAM is that it does not have any moving parts while the biggest advantage of Rom is that it is not lost when power is switched off.

Characteristics of RAM

Here, are some essential characteristics of RAM: the volatile memory

  • RAM chips are widely used in the normal operations of a computer for starting and loading the operating system and applications.
  • Much faster to read from and write
  • Data in RAM stays there until the computer is running
  • A RAM chip allows you to store multiple gigabytes (GB) of data.
  • A 32 bit PC can have a maximum of 4 GB of RAM while a 64 bit PC can have 16 exabytes of RAM

Characteristics of ROM

Here, are some important characteristics of ROM memory

  • You can write data only once. However, once it is written, you can read it any number of times
  • A ROM chip is used mainly in the start-up process of a modern computer
  • A ROM, non-volatile memory stores only several megabytes (MB) of data, up to 4 MB or more per chip

Types of RAM

Here are types of RAM:

  • DRAM -Dynamic RAM must be continuously refreshed, or otherwise, all contents are lost.
  • SRAM - Static RAM is faster, needs less power but is more expensive. However, it does need to be refreshed like DRAM.
  • Synchronous Dynamic RAM (SDRAM) - This type of RAM can run at very high clock speeds.
  • DDR - Double Data Rate provide synchronous Random Access Memory

Types of ROM

Here are important types of ROM memory.

  • EPROM: The full form of EPROM is Erasable Programmable Read-only memory. It stores instructions, but you can erase only by exposing the memory to ultraviolet light.
  • PROM: The full form of PROM is Programmable Read-Only memory. This type of ROM is written or programmed using a particular device.
  • EEPROM stands for electrically Erasable Programmable Read-Only Memory. It stores and deletes instructions on a special circuit.
  • Mask ROM is a full form of MROM is a type of read-only memory (ROM) whose contents can be programmed only by an integrated circuit manufacturer.

Differences between RAM and ROM

Parameters RAM ROM
Usage RAM allows the computer to read data quickly to run applications. ROM stores all the application which is needed to boot the computer initially. It only allows for reading.
Volatility RAM is volatile. So, its contents are lost when the device is powered off. It is non-volatile, i.e., its contents are retained even if the device is powered off
Accessibility Information stored in the RAM is easily accessed. The processor can't directly access the information that is stored in the ROM. In order to access ROM information first, the information is transferred into the RAM, and then it can be executed by the processor.
Read/Write Both R (read) and W (write) operations can be performed over the information which is stored in the RAM. The ROM memory allows the user to read the information. But, the user can't alter the information.
Storage RAM is used to store temporary information. ROM memory is used to store permanent information, which is non-erasable.
Speed The access speed of RAM is faster. Its speed is slower in comparison with RAM. Therefore, ROM can't boost up the processor speed.
Cost The price of RAM is quite high. The price of ROM is comparatively low.
Chip size Physical size of RAM chip is bigger than ROM chip. Physical size of ROM chip is smaller than the RAM chip of same storage capacity.
Preservation of Data Electricity is needed in RAM to flow and to preserve information Electricity is not required to flow and preserving information
Structure The RAM chip is in rectangle form and is inserted over the motherboard of the computer. Read-only memory (ROM) is a type of storage medium that permanently stores data on personal computers (PCs) and other electronic devices.

Advantage of RAM

Here, are some important advantages of using RAM

  • Silent: RAM does not have any moving parts, so its operation is completely silent.
  • Power-efficient: RAM uses much less power than disk drives.
  • Saves your system battery: It helps you to reduce carbon emissions and extend your battery life.

Advantages of ROM

Here, are some important advantages of using ROM

  • This memory is not lost when power is switched off. Therefore, it is called non-volatile memory.
  • It can't be changed accidentally
  • Cheaper than RAMs
  • Static and do not require refreshing

Comparison of various memory storage devices

Here, is a comparison between a various storage device

Storage Speed Cost Capacity Permanent
Register Fastest Highest Lowest No
Hard Disk Moderate Very Low Very High Yes
RAM Very fast High Low to Moderate No
ROM Very Fast High Very Low Yes
CD-ROM Moderate Very Low High Yes