There are several major differences between a ROM (read-only memory) chip and a RAM (random-access memory) chip. The differences revolve around how they’re used, storage capabilities and capacity, and physical sizes of ROM and RAM chips.

Select a link below for details of the differences and additional information about ROM and RAM.

Table of differences

Further explanation of differences

Storage capabilities of ROM and RAM

A ROM chip is a non-volatile storage medium, which means it does not require a constant source of power to retain the information stored on it. By contrast, a RAM chip is volatile, which means it loses any information it is holding when the power is turned off. Essentially, ROM is used for permanent storage, and RAM is for temporary storage.

  • Table of differences
  • Further explanation of differences
  • Computer ROM
  • Computer RAM

Uses of ROM and RAM

A ROM chip is used primarily in the startup process of a computer, whereas a RAM chip is used in the normal operations after the operating system is loaded. For example, a ROM chip is often used to store the BIOS program on the motherboard. A RAM chip temporarily stores files in use on a computer, like a document you’re writing, an image you’re editing, or data for a game you’re playing.

Storage capacity of ROM and RAM

A ROM chip stores several MB (megabytes) of data, usually 4 to 8 MB per chip, whereas a RAM chip can store multiple GB (gigabytes) of data, ranging from 1 to 256 GB per chip.

Computer ROM

An example of ROM is the computer BIOS, a PROM chip that stores the programming needed to begin the initial computer startup process. Using a non-volatile storage medium is the only way to begin this process for computers and other devices. ROM chips were also used in gaming system cartridges, like the original Nintendo, Gameboy, Sega Genesis, and others.

The oldest ROM-type storage medium can be dated back to 1932 with drum memory. ROM-type storage is still used today.

Computer RAM

RAM chips are used in computers and other devices to store temporary information produced by programs quickly. RAM is one of the fastest types of memory, allowing it to switch quickly between tasks. For example, the Internet browser you are using to read this page is loaded into RAM and is running from it.

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