Difference Between RAM and ROM

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Difference Between RAM and ROM

Gaurav Roy
Last updated on December 11, 2022

    RAM and ROM are two of the most important memories of a computer system. In this article, we will discuss the difference between RAM and ROM, but before that, let's know about the two.

    What is Random Access Memory (RAM)?

    The full form of RAM is Random Access Memory. All of the information stored in this memory is lost when the power supply to the system is switched off. The complete information stored in RAM can be checked through BIOS (Basic Input/Output System). It is also called main memory, cache memory, temporary memory, or volatile memory of a computer system. It is used to store the programs and data being used by the CPU in real-time. The data in RAM can be read, written, and erased any number of times. RAM is a hardware element where the data being currently used is stored. It is a volatile memory.

    Types of RAM

    1. Static RAM (SRAM): This type of RAM stores data using the state of a six-transistor memory cell.
    2. Dynamic RAM (DRAM): This type of RAM stores data using a pair of transistors and capacitors.

    Characteristics of RAM

    • RAM chips are widely used in the normal operations of a computer. For instance, starting and loading the operating system and system applications.
    • It is 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 up to 16 exabytes of RAM.

    Benefits of RAM

    • Silent Operation : RAM does not have any moving parts. Thus, its operation is completely silent.
    • Power-efficient : RAM uses much less power than disk drives.
    • Extends Battery Life : It helps you to reduce carbon emissions and enhance battery life.

    What is Read-Only Memory (ROM)?

    It is a type of memory where the data has been pre-recorded. Data stored in ROM is retained even after the computer is turned off. Hence, it is a non-volatile memory.

    Types of ROM

    1. Programmable ROM (PROM): In this type of ROM, the data is written after the memory chip has been created. It is non-volatile.
    2. Erasable Programmable ROM (EPROM): The data on this non-volatile memory chip can be erased by exposing it to high-intensity UV light.
    3. Electrically Erasable Programmable ROM (EEPROM): In EEPROM, the data on this non-volatile memory chip can be electrically erased using field electron emission.
    4. Mask ROM ( MROM ): In this type of ROM, the data is written during the manufacturing of the memory chip.

    Characteristics of ROM

    • You can write data only once on ROM. 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 chip can store only several megabytes (MB) of data, up to 4 MB or more per chip.

    Benefits of ROM

    • This memory is not lost when the power is switched off. Therefore, it is called non-volatile memory.
    • It can't be changed accidentally.
    • ROM is cheaper than RAM.
    • It is static and does not require refreshing.

    Difference Between RAM and ROM: A Head-to-Head Comparison

    Factors RAM ROM
    Usage RAM allows the computer to read data quickly to run applications. ROM stores all the applications that are 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 accessible. The processor can't directly access the information stored in the ROM. In order to access the same, 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 stored in the random access memory. Read-only memory allows the user to read the information. But, the user can't alter the information.
    Storage RAM stores temporary information. ROM stores permanent information, which is non-erasable.
    Speed The access speed of RAM is faster. Its access 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 The physical size of the RAM chip is bigger than the ROM chip. The physical size of the ROM chip is smaller than the RAM chip of the same storage capacity.
    Preservation of Data Electricity is needed in RAM to preserve information. Electricity is not required to preserve the information.
    Structure A RAM chip is in a rectangular form, and it is inserted into 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.


    In this article, we provided complete information regarding the difference between RAM and ROM. RAM stands for random access memory. All of the information stored in this memory is lost when the power supply to the computer or laptop is switched off. Hence, it is a volatile memory. ROM is read-only memory, and it is an important computer memory that stores information that doesn't require changes. It retains the data even when the power is not available. Although comparisons are often drawn between RAM and ROM, both are important for running computer systems. This means one is not the replacement for the other.

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