Random access memory (RAM) is the computer's working space. It holds data and instructions that the processor needs while programs are running. Its contents are normally lost when the computer turns off, unlike files kept on an SSD.
Why programs need RAM
When you open an application, the operating system loads the parts it needs from storage into RAM. Open documents, browser tabs and background tasks also use memory. The CPU can reach this working data much faster than it can read from storage.
If active programs need more memory than is available, the operating system may move some data to storage temporarily. This allows work to continue, but switching back to that data can be noticeably slower. A full memory meter is therefore a clue to investigate, not a rule that every computer needs an upgrade.
Capacity, speed and compatibility
Capacity is measured in gigabytes (GB) and describes how much working data fits. Speed and latency describe different aspects of how quickly data can be transferred and accessed. For most people, adequate capacity comes before small differences in speed.
Memory must also match the motherboard and processor. Desktop and laptop modules have different shapes, and DDR4 and DDR5 are different generations that do not fit the same slot. Check the computer or motherboard manual before buying a module.
RAM is not storage
RAM is temporary working space. An SSD keeps the operating system, applications and personal files when power is removed. A computer with a large SSD can still run short of RAM when many demanding programs are open. Conversely, adding RAM does not increase the amount of disk space available for files.
How to check what you have
Windows 11 shows installed memory in Settings → System → About. Our step-by-step guide also explains how to see current memory use. If you intend to upgrade a desktop, read the installation guide after checking compatibility.