Random Access Memory

What Does Random Access Memory Mean?

Random access memory (RAM) is a type of data storage used in computers that is generally located on the motherboard. It is the main memory used by a computer for quick access since is much faster to read and write than other forms of storage—between 20-100 times faster than hard disks.


Each storage location inside the memory can be accessed independently of the address, meaning that every location can be reached easily at the same time (hence the term “random”). RAM is a volatile type of memory, meaning that all information that was stored in RAM is lost when the computer is turned off. Volatile memory is temporary memory while ROM (read-only memory) is non-volatile and holds data permanently when the power is turned off.

RAM is a short-term access memory used to rapidly perform immediate tasks, but it is inherently limited. Every time the computer needs to work on an application or program, the RAM is used to complete that operation. However, since it’s volatile, no data can be stored on RAM permanently, so a long-term storage such as a hard drive is required.

When the RAM fills up, the computer processor must go back and forth to unload that data in the hard disk. Therefore, the smaller the amount of RAM, the slower the computer’s operations. A basic amount of RAM is 4 GB, but for gaming systems and high end work stations, up to 16 or 32 GB can be required for optimal performance.

A RAM chip may be individually mounted on the motherboard or in sets of several chips on a small board connected to the motherboard.

The three main memory circuit boards types containing chips are:

Most motherboards today use DIMMs.

Techopedia Explains Random Access Memory

RAM is used to increase the speed of applications by loading information into it to be accessed as quickly as possible. It is also used to increase the availability of previously-accessed data. For example, when a program is launched for the first time after a reboot, it takes more time since the computer is loading it from long-term storage.

If the software is closed and reopened, though, the operation will occur almost instantly since it’s now loaded from the much faster RAM. RAM is employed for any operation that requires rapid access to computing resources, such as accessing many of the operating system’s drivers that are loaded into it every time the computer is booted up.

There are two main types of RAM: dynamic random access memory (DRAM), or Dynamic RAM, and static random access memory (SRAM). The RAM in most personal computers (PC’s) is Dynamic RAM. All dynamic RAM chips on DIMMs, SIMMs or RIMMs have to refresh every few milliseconds by rewriting the data to the module.

Static RAM (SRAM)

Static RAM (SRAM) is volatile memory and is often used in cache memory and registers because it is a lot faster and does not require refreshing like Dynamic RAM. As long as power is supplied, SRAM retains its content and there’s no need to refresh it on a regular basis.

SRAM uses a matrix of 6-transistors that do not depend on power to avoid leakages since they act as switches serving as 1s and 0s with no capacitor holding the charge. However, since more transistors are needed than a DRAM, the matrix requires extra space, making the manufacturing costs higher.

An SRAM is able to operate at higher speed and uses less power than a DRAM, but is also more expensive and is thus used only as the processor’s cache memory. SRAM is used in memory cache on the central processing unit (CPU); it is called L1, L2 and L3 cache. Original SRAM was stored on the motherboard; later SRAM was inside of the CPU housing or stored on both the motherboard and inside of the CPU.

Dynamic RAM (DRAM)

Dynamic RAM is memory that needs refreshing. The refreshing is done by the memory controller which is part of the chipset on the motherboard. Each cell is held in an electrical capacitor with transistors serving as gates that determine whether each value could be read or written. To compensate for the capacitor’s leaks, the DRAM must be refreshed with an electronic charge that rewrites the data every few milliseconds. DRAMs are usually smaller and less expensive than SRAMs and are used in practically every PC.


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Margaret Rouse

Margaret Rouse is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical, business audience. Over the past twenty years her explanations have appeared on TechTarget websites and she's been cited as an authority in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine and Discovery Magazine.Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages. If you have a suggestion for a new definition or how to improve a technical explanation, please email Margaret or contact her…