Every computing device has storage devices installed to save instructions, data, and files. These storage devices are categorised into two types — primary and secondary storage devices. Primary storage devices are a necessity for the system to run and function, while secondary storage devices are a permanent storage solution that can be present as an internal or external device.

Random Access Memory and Read-Only Memory are two types of primary storage devices present on different computing devices. RAM provides temporary storage for files and is also known as the main memory of the system. RAM support depends on the OS of the system as a 32-bit OS supports up to 4 GB of RAM while a 64-bit system supports up to 16 exabytes of RAM.

ROM or Read-Only Memory is a permanent primary storage device which can only contain a small amount of data. The contents of ROM are mostly written by the manufacturer, which helps in saving vital information or instructions from alteration by users; like firmware. Even though RAM and ROM are primary storage devices, they still differ from each other a lot.

Although basic terms, the two terms can confuse many PC users. Here we see how RAM and ROM differ as we compare them on seven different parameters below.

RAM vs ROM

Volatility: RAM is a volatile storage device, while ROM is non-volatile. A volatile storage device works only when power is provided and loses the contents stored on it after power is turned off. ROM keeps the data saved even after power is switched off.
Use: RAM is used to store the files required by the CPU for processing, or any intermediate files, or output files before it sends them to secondary storage devices temporarily. ROM often stores the BIOS program or Firmware modules of the system, which is basically the instructions for the computer.
Speed: Both of them are very high-speed storage devices. Comparing both of them, RAM is a faster storage device compared to ROM. The frequency of a DDR4 SDRAM is between 800 and 1600 MHz and operates at a voltage of 1.2 V.
Read/Write Access: The data on RAM can be read, altered, and written by a user. ROM, on the other hand, allows the user only to read the data. Data can only be written on ROM once.
Accessibility: Data stored on RAM is easily accessible by the CPU and the user, while the data stored on the ROM needs to be loaded onto RAM. A processor or user can only access the data after it’s loaded on RAM.
Capacity: RAM and ROM come in different sizes according to the needs of the user. RAM chips can offer a size of 16 MB to 256 GB. ROM chips usually provide a storage capacity of 4 to 8 MB. RAM has a much larger storage capacity than ROM.
Cost: RAM is a significantly costlier storage device than ROM.