Alternatively referred to as main memory, primary memory, or system memory, Random Access Memory (RAM) is a computer storage location that allows information to be stored and accessed quickly from random locations within DRAM on a memory module. Because information is accessed randomly instead of sequentially like it is on a CD or hard drive, the computer can access the data much faster. However, unlike ROM and the hard drive RAM is a volatile memory and requires power in order to keep the data accessible, if power is lost all data contained in memory lost.

As the computer boots up, parts of the operating system and drivers are loaded into memory, which allows the CPU to process the instructions much faster, hence taking less time before your machine is operational. After the operating system has loaded, each program you open such as the browser you're using to view this page is loaded into memory while it is running. If too many programs are open the computer will swap the data in the memory between the RAM and the hard disk drive.

Over the evolution of computers there has been different variations of RAM used in computer. Some of the more common examples are DIMM, RIMM, SIMM, SO-DIMM, and SOO-RIMM. Below is an example image of a 512MB DIMM computer memory module and what the typical desktop computer memory card will look like. This memory module would be installed into memory slots on the motherboard.

Computer DIMM or dual-inline memory module

Tip: New users often confuse memory (RAM) with disk drive space. See our memory definition for a comparison between memory and storage.

Related pages

Also see: DIMM, Dynamic storage, Memory, Memory terms, Primary storage, RDRAM, SIMM, SDRAM, Volatile memory