What is RAM (Random Access Memory)? - Definition from SearchStorage (2023)

What is RAM?

RAM (Random Access Memory) is the hardware in a computing device where the operating system (OS), application programs and data in current use are kept so they can be quickly reached by the device'sprocessor. RAM is the main memory in a computer. It is much faster to read from and write to than other kinds of storage, such as a hard disk drive (HDD), solid-state drive (SSD) or optical drive.

Random Access Memory is volatile. That means data is retained in RAM as long as the computer is on, but it is lost when the computer is turned off. When the computer is rebooted, the OS and other files are reloaded into RAM, usually from an HDD or SSD.

Function of RAM

Because of its volatility, RAM can't store permanent data. RAM can be compared to a person's short-term memory, and a hard disk drive to a person's long-term memory. Short-term memory is focused on immediate work, but it can only keep a limited number of facts in view at any one time. When a person's short-term memory fills up, it can be refreshed with facts stored in the brain's long-term memory.

A computer also works this way. If RAM fills up, the computer's processor must repeatedly go to the hard disk to overlay the old data in RAM with new data. This process slows the computer's operation.

What is RAM (Random Access Memory)? - Definition from SearchStorage (1)

A computer's hard disk can become completely full of data and unable to take any more, but RAM won't run out of memory. However, the combination of RAM and storage memory can be completely used up.

How does RAM work?

The termrandom access as applied to RAM comes from the fact that any storage location, also known as any memory address, can be accessed directly. Originally, the termRandom Access Memory was used to distinguish regular core memory from offline memory.

Offline memory typically referred tomagnetic tapefrom which a specific piece of data could only be accessed by locating the address sequentially, starting at the beginning of the tape. RAM is organized and controlled in a way that enables data to be stored and retrieved directly to and from specific locations.

Other types of storage -- such as the hard drive andCD-ROM-- are also accessed directly or randomly, but the termrandom access isn't used to describe these other types of storage.

RAM is similar in concept to a set of boxes in which each box can hold a 0 or a 1. Each box has a unique address that is found by counting across the columns and down the rows. A set of RAM boxes is called anarray, and each box is known as a cell.

To find a specific cell, the RAM controller sends the column and row address down a thin electrical line etched into the chip. Each row and column in a RAM array has its own address line. Any data that's read flows back on a separate data line.

(Video) What is DRAM? How is it Different From SRAM?

RAM is physically small and stored inmicrochips. It's also small in terms of the amount of data it can hold. A typical laptop computer may come with 8 gigabytes of RAM, while a hard disk can hold 10 terabytes.

A hard drive, on the other hand, stores data on the magnetized surface of what looks like a vinyl record. Alternatively, an SSD stores data in memory chips that, unlike RAM, are nonvolatile. They don't depend on having constant power and won't lose data once the power is turned off. RAM microchips are gathered together into memory modules. These plug into slots in a computer's motherboard. A bus, or a set of electrical paths, is used to connect the motherboard slots to the processor.

Most PCs enable users to add RAM modules up to a certain limit. Having more RAM in a computer cuts down on the number of times the processor must read data from the hard disk, an operation that takes longer than reading data from RAM. RAM access time is in nanoseconds, while storage memory access time is in milliseconds.

How much RAM do you need?

The amount of RAM needed all depends on what the user is doing. When video editing, for example, it's recommended that a system have at least 16 GB RAM, though more is desirable. For photo editing using Photoshop, Adobe recommends a system have at least 3GB ofRAMto runPhotoshopCC on a Mac. However, if the user is working with other applications at the same time, even 8GB of RAM can slow things down.

Types of RAM

RAM comes in two primary forms:

  • Dynamic Random Access Memory (DRAM) makes up the typical computing device's RAM, and as was previously noted, it needs that power to be on to retain stored data.

Each DRAM cell has a charge or lack of charge held in an electrical capacitor. This data must be constantly refreshed with an electronic charge every few milliseconds to compensate for leaks from the capacitator. A transistor serves as a gate, determining whether a capacitor's value can be read or written.

  • Static Random Access Memory (SRAM) also needs constant power to hold on to data, but it doesn't need to be continually refreshed the way DRAM does.

In SRAM, instead of a capacitor holding the charge, the transistor acts as a switch, with one position serving as 1 and the other position as 0. Static RAM requires several transistors to retain one bit of data compared to dynamic RAM which needs only one transistor per bit. As a result, SRAM chips are much larger and more expensive than an equivalent amount of DRAM.

However, SRAM is significantly faster and uses less power than DRAM. The price and speed differences mean static RAM is mainly used in small amounts as cache memory inside a computer's processor.

(Video) What is DIMM (Dual In-line Memory Module)?

What is RAM (Random Access Memory)? - Definition from SearchStorage (2)

History of RAM: RAM vs. SDRAM

RAM was originally asynchronous because the RAM microchips had a different clock speed than the computer's processor. This was a problem as processors became more powerful and RAM couldn't keep up with the processor's requests for data.

In the early 1990s, clock speeds were synchronized with the introduction of synchronous dynamic RAM, or SDRAM. By synchronizing a computer's memory with the inputs from the processor, computers were able to execute tasks faster.

However, the original single data rate SDRAM (SDR SDRAM) reached its limit quickly. Around the year 2000, double data rate synchronous Random Access Memory (DDR SRAM) was developed. This moved data twice in a single clock cycle, at the start and the end.

DDR SDRAM has evolved three times, with DDR2, DDR3 and DDR4, and each iteration has brought improved data throughput speeds and reduced power use. However, each DDR version has been incompatible with earlier ones because, with each iteration, data is handled in larger batches.

What is RAM (Random Access Memory)? - Definition from SearchStorage (3)


Graphics double data rate (GDDR) SDRAM is used in graphics and video cards. Like DDR SDRAM, the technology enables data to be moved at various points in a CPU clock cycle. However, it runs at higher voltages and has less strict timing than DDR SDRAM.

With parallel tasks, such as 2D and 3D video rendering, tight access times aren't as necessary, and GDDR can enable the higher speeds and memory bandwidth needed for GPU performance.

Similar to DDR, GDDR has gone through several generations of development, with each providing more performance and lower power consumption. GDDR6 is the latest generation of graphics memory.

RAM vs. virtual memory

A computer can run short on memory, especially when running multiple programs simultaneously. Operating systems can compensate for physical memory shortfalls by creating virtual memory.

With virtual memory, data is temporarily transferred from RAM to disk storage, and virtual address space is increased using active memory in RAM and inactive memory in an HDD to form contiguous addresses that hold an application and its data. Using virtual memory, a system can load larger programs or multiple programs running at the same time, letting each operate as if it has infinite memory without having to add more RAM.

(Video) What is Virtual Memory? What Does it Do?

Virtual memory is able to handle twice as many addresses as RAM. A program's instructions and data are initially stored at virtual addresses, and once the program is executed, those addresses are turned into actual memory addresses.

One downside to virtual memory is that it can slow a computer because data must be mapped between the virtual and physical memory. With physical memory alone, programs work directly from RAM.

RAM vs. flash memory

Flash memory and RAM are both comprised of solid-state chips. However, they play different roles in computer systems because of differences in the way they're made, their performance specifications and cost. Flash memory is used for storage memory. RAM is used as active memory that performs calculations on the data retrieved from storage.

One significant difference between RAM and flash memory is that data must be erased from NAND flash memory in entire blocks. This makes it slower than RAM, where data can be erased in individual bits.

However, NAND flash memory is less expensive than RAM, and it's also nonvolatile. Unlike RAM, it can hold data even when the power is off. Because of its slower speed, nonvolatility and lower cost, flash is often used for storage memory in SSDs.


Read-only memory, or ROM, is computer memory containing data that can only be read, not written to. ROM contains boot-up programming that is used each time a computer is turned on. It generally can't be altered or reprogrammed.

The data in ROM is nonvolatile and isn't lost when the computer power is turned off. As a result, read-only memory is used for permanent data storage. Random Access Memory, on the other hand, can only hold data temporarily. ROM is generally several megabytes of storage, while RAM is several gigabytes.

Trends and future directions

Resistive Random Access Memory (RRAM or ReRAM) is nonvolatile storage that can alter the resistance of the solid dielectric material it's composed of. ReRAM devices contain a memristor in which the resistance varies when different voltages are applied.

ReRAM creates oxygen vacancies, which are physical defects in a layer of oxide material. These vacancies represent two values in a binary system, similar to a semiconductor's electrons and holes.

(Video) What is VRAM and Why is it Important?

ReRAM has a higher switching speed compared to other nonvolatile storage technologies, such as NAND flash. It also holds the promise of high storage density and less power consumption than NAND flash. This makes ReRAM a good option for memory in sensors used for industrial, automotive and internet of things applications.

Vendors have struggled for years to develop ReRAM technology and get chips into production. A few vendors are currently shipping them.

3D XPoint technology, such as Intel's Optane, could eventually fill the gap between dynamic RAM and NAND flash memory. 3D XPoint has a transistor-less, cross-point architecture in which selectors and memory cells are at the intersection of perpendicular wires. 3D XPoint isn't as fast as DRAM, but it is nonvolatile memory.

What is RAM (Random Access Memory)? - Definition from SearchStorage (4)

In terms of performance and price, 3D XPoint technology is between fast, but costly DRAM and slower, less expensive NAND flash. As the technology develops, it may blur the distinction between RAM and storage.

5G and the RAM market

In February 2019, theJEDEC Solid State Technology Associationpublished theJESD209-5, Low Power Double Data Rate 5 (LPDDR5). LPDDR5 will eventually operate at an I/O rate of 6400 MT/s, 50 percent higher than that of the first version of LPDDR4. This will significantly boost memory speed and efficiency for a variety of applications. This includes mobile computing devices such as smartphones, tablets and ultra-thin notebooks.

LPDDR5 was published with a data rate of 6400 MT/s, compared to 3200 MT/s for LPDDR4 at its publication in 2014.

In July 2019, Samsung Electronics began mass producing the industry’s first 12-gigabit LPDDR5 mobile DRAM. According to Samsung, it has been optimized for enabling 5G and AI features in future smartphones.

Cost of RAM

By the summer of 2019, DRAM prices remained depressed from earlier levels -- but volatile, nonetheless. A number of variables contributed to the volatility, including:

  • a supply glut
  • market tensions between South Korea and Japan (home to the world's two largest memory chip makers, Samsung and SK Hynix)
  • the introduction of the next-generation mobile chip, the LPDDR5
  • the increased adoption of 5Gtechnology
  • an anticipated increase in demand for consumer electronics in the Internet of Things (IoT), such as automobiles and wearable devices, which use the chips


What is RAM explained random-access memory? ›

RAM is a temporary memory bank where your computer stores data it needs to retrieve quickly. RAM keeps data easily accessible so your processor can quickly find it without having to go into long-term storage to complete immediate processing tasks.

What is a RAM in short answer? ›

RAM stands for random-access memory, but what does that mean? Your computer RAM is essentially short term memory where data is stored as the processor needs it. This isn't to be confused with long-term data that's stored on your hard drive, which stays there even when your computer is turned off.

What is the meaning of RAM memory? ›

RAM is a common computing acronym that stands for random-access memory. Sometimes it's called PC memory or just memory. In essence, RAM is your computer or laptop's short-term memory. It's where the data is stored that your computer processor needs to run your applications and open your files.

What is a RAM quizlet? ›

Alternatively referred to as main memory, primary memory, or system memory, Random Access Memory (RAM) is a hardware device that allows information to be stored and retrieved on a computer. RAM is usually associated with DRAM, which is a type of memory module.

Why is RAM random-access memory important? ›

RAM allows your computer to perform many of its everyday tasks, such as loading applications, browsing the internet, editing a spreadsheet, or experiencing the latest game. Memory also allows you to switch quickly among these tasks, remembering where you are in one task when you switch to another task.

What is the main purpose of the types of RAM? ›

It is used mainly to start or boot up a computer. Once the operating system is loaded, the computer uses RAM, which stands for random-access memory, which temporarily stores data while the central processing unit (CPU) is executing other tasks.

Which best defines RAM? ›

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.

What does RAM stand for random access memory quizlet? ›

RAM stands for random access memory, a form of memory that holds its contents even if the current is turned off or disrupted.

What is the function of RAM quizlet? ›

RAM is the type of memory used in the computer's main memory. The main purpose of RAM is to act as temporary storage for programs and data, just for the duration of that program. ROM is Read Only Memory; you cannot write over the contents once it has been created.

What is the important feature of RAM? ›

Computer random access memory (RAM) is one of the most important components in determining your system's performance. RAM gives applications a place to store and access data on a short-term basis. It stores the information your computer is actively using so that it can be accessed quickly.

What is the importance of RAM memory? ›

The more RAM your CPU has access to, the easier its job becomes, which enables a faster computer. If you do not have a sufficient amount of RAM than your CPU has to work much, much harder to transfer data, which severally damages the computer's performance. Random access memory also helps your system support software.

How does RAM store data? ›

Random access memory is made up of memory cells, and each memory cell can store a single bit of data: either a zero or a one. Put simply, the cells are connected in a grid made up of address lines and perpendicular bit lines. By specifying an address line and a bit line, each individual cell is uniquely addressable.

What is RAM and how much is good? ›

How much RAM do you need? Generally, we recommend 8GB of RAM for casual computer usage and internet browsing, 16GB for spreadsheets and other office programs, and at least 32GB for gamers and multimedia creators. How you use your computer influences how much RAM you need, so use this as a guideline.

Where is RAM stored? ›

RAM, stands for Random Access Memory, is a hardware device generally located on the motherboard of a computer and acts as an internal memory of the CPU. It allows the CPU to store data, program, and program results when you switch on the computer.

Which of the following is the best definition for RAM quizlet? ›

-This is correct. RAM stands for Random Access Memory. This memory is used to store information short-term, such as instructions to be executed and values to be used in the execution of these instructions.

Which of the following is true about RAM random-access memory )? ›

Detailed Solution. The correct answer is Random access, volatile, and a semiconductor memory. RAM stands for Random Access Memory. Random-access memory is a form of computer memory that can be read and changed in any order, typically used to store working data and machine code.

What is RAM difference between RAM and ROM? ›

RAM is a form of computer memory that can be read and changed in any order, typically used to store working data and machine code. ROM is a type of non-volatile memory used in computers and other electronic devices.

What is the purpose of RAM quizlet? ›

RAM is the type of memory used in the computer's main memory. The main purpose of RAM is to act as temporary storage for programs and data, just for the duration of that program.

What access does RAM use? ›

Random Access Memory

It works by storing common data that programs are in constant use of, rather than storing the data on a much slower medium like a Solid State Hard Drive (or SSD). RAM doesn't automatically have data saved on each chip though.

How data is stored in RAM? ›

Random Access Memory is volatile. That means data is retained in RAM as long as the computer is on, but it is lost when the computer is turned off. When the computer is rebooted, the OS and other files are reloaded into RAM, usually from an HDD or SSD.

What is the importance of RAM? ›

RAM is important because it's a key factor in determining how your computer functions. Without enough RAM, your programs and games may lag or not function at all. RAM works with the hard drive and other computer components to transfer and store information.

What is the difference between RAM & ROM give examples of each? ›

ROM stands for read only memory. It is a non-volatile memory that stores information permanently, even when the power is turned off.
What is ROM:
Examples: It is used as CPU Cache, Primary Memory in a computer.Examples: It is used as Firmware by micro-controllers.
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