What’s the difference between RAM and ROM?

The difference between RAM and ROM, like so many things in computing is relatively simple, but the acronyms sound so similar that confusion is inevitable and understandable. So, we’re going to explain what RAM is, what ROM is, and their similarities and differences today.

RAM stands for Random Access Memory, and ROM stands for Read Only Memory.

RAM is memory that stores the data that you’re currently working with, but it’s volatile, meaning that as soon as it loses power, that data disappears.

ROM refers to permanent memory. It’s non-volatile, so when it loses power, the data remains. This makes it perfect for things that don’t change, like the BIOS of your motherboard.

Random Access Memory is used to temporarily store data while the computer is on. This means that when you switch between programs that you’ve recently opened, the data has been kept in the RAM. This allows the computer to retrieve it far more quickly.

This is why opening a program takes so much longer than simply switching back to it. Opening a program makes the PC get data from your SSD or HDD, which are comparatively slow. Switching to a program that’s already open, or sometimes even recently closed is quicker because RAM is far faster than storage.

Read Only Memory, is a permanent, non-volatile type of memory. It generally can’t be changed after it’s created, only accessed, hence the name. It’s vital for your computer, as ROM is the perfect place to store important data and instructions that won’t change. The data is not affected by a loss of power, like RAM is.

Think of ROM not like traditional “storage”, and more like a really safe spot to keep sets of instructions. These instructions need to be accessible by the boot-up sequence and the UEFI BIOS for example. This is why it’s so important that it’s non-volatile.

Technically, there are types of read-only memory that can actually be re-written, like EEPROM. However, this is beyond the scope of this article. We aren’t trying to give you a total re-education in computing right now, just to give you a rundown of the basics.