RAM vs. ROM: What's the Difference?
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RAM (random-access memory) is fast, volatile working memory that holds the programs and data in use right now and loses them when power is switched off, while ROM (read-only memory) is non-volatile memory that keeps its contents without power and stores firmware such as startup code. In modern devices, ROM is usually flash memory that can be rewritten during firmware updates.
At a glance
| RAM | ROM | |
|---|---|---|
| Volatility | Volatile: loses data when power goes off | Non-volatile: keeps data without power |
| Reading and writing | Read and written constantly by the processor | Mostly read; rewritten rarely, e.g. firmware updates |
| Main job | Holds running apps and open files | Stores firmware such as BIOS/UEFI startup code |
| Typical size | Several gigabytes, e.g. 8 to 16 GB in a laptop | Megabytes for a PC's firmware chip |
| Speed | Very fast, built for constant access | Slower to write; reads fast enough for booting |
Which should you use?
More RAM helps when many apps or browser tabs stay open at once: a phone with 8 GB of RAM can keep more apps paused in the background instead of reloading them.
ROM-type memory holds code that must survive power-off and run first, such as the firmware in a washing machine's controller or the UEFI chip that starts a laptop.