Random Access Memory (RAM)

Image of RAM memory.
Random Access Memory (RAM) reviewed by Web Webster

 

Random Access Memory (RAM) is a high-speed component in devices that temporarily stores all information a device needs for the present and future. It’s a type of computer memory that can be randomly accessed, meaning any byte of memory can be accessed without touching the preceding bytes. RAM is found in servers, PCs, tablets, smartphones, backup drives and other devices. In today’s technology, RAM takes the form of integrated circuit chips with metal-oxide-semiconductor (MOS) memory cells.

The speed and performance of a system is directly correlated with the amount of RAM installed.

RAM stores the information a computer is actively using so that it can be accessed quickly. It allows computers to perform everyday tasks such as loading applications, browsing the internet, editing a spreadsheet, and switching quickly among all these tasks.

Types of RAM

There are two main types of RAM that contrast in both performance and price range:

  • Static Random Access Memory (SRAM): a memory chip that is faster and uses less power than DRAM
  • Dynamic Random Access Memory (DRAM): a memory chip that can hold more data than an SRAM chip but requires more power.

The chart below from Enterprise Storage Forum details the difference of SRAM vs. DRAM in computers:

Feature

DRAM

SRAM

Cost

Cheaper

More expensive

Performance

Slower: Off-chip memory with longer access time

On-chip memory with minimal access time; can run at the speed of the host microprocessor

Use case

Main memory

Level 1 and Level 2 microprocessor caches

Density

Less density per cell (1 transistor per chip) but can pack more cells into space

Denser (6 transistors per chip) but can fit fewer cells into space

Power

Generally higher: Capacitors leak power thanks to imperfect insulation, requiring regular power refreshes.

Generally lower: No charge leakage since it changes direction of current through switches instead of leaking power through the capacitor. However, this depends on the application environment and SRAM can consume as much or more power as DRAM.

Storage capacity

Larger: Connects directly to CPU bus, volatile storage measured in GBs

Smaller: Acts as cache; storage measured in MBs

Volatility

Volatile: Must have active power supply plus frequent charges while active.

Volatile: Does not require additional charges while it is receiving power, but eventually loses data without it.

Physical placement

Motherboard

Processors or between processor and main memory

RAM vs. memory vs. storage

In common usage, the term RAM is synonymous with main memory, where a computing system stores data that it is actively using. Storage systems, such as hard drives, network storage devices or cloud storage, are where a system saves data that it will need to access later. Memory and storage are often confused with one another because both are measured in megabytes, gigabytes, and terabytes.

Computing systems can retrieve data from RAM quickly, but when a device powers down,

 

all data that was in memory goes away. If an unexpected power outage or system crash occurs, unsaved documents or files are lost because the data was stored in system memory, which is volatile.

By contrast, storage is slower, but it can retain data when the device is powered down. So, for example, if a document has been saved to a hard drive prior to a power outage or system crash, the user will still be able to retrieve it when the system is back up and running. Storage is usually less expensive than RAM on a per-gigabyte basis. As a result, most PCs and smartphones have many times more gigabytes of storage than gigabytes of RAM. The growing use of solid-state drives has blurred the line between memory and storage.

RAM vs. ROM

Random access memory is different from read-only memory (ROM). ROM is memory to which programming has been permanently written. ROM cannot be altered, and its contents are retained even when the computer has no power. RAM is constantly overwritten when the device is in operation.

Vangie Beal
Vangie Beal is a freelance business and technology writer covering Internet technologies and online business since the late '90s.

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