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, 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.
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