Random Access Memory

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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's processor. RAM is the main memory in a computer, and 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.

How does RAM work?

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

Offline memory typically referred to magnetic tape from 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 and CD-ROM-- are also accessed directly or randomly, but the term random 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 an array, 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.

RAM is physically small and stored in microchips. 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.

RAM microchips are gathered together into memory modules, which 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.

A hard drive, on the other hand, stores data on the magnetized surface of what looks like a vinyl record. And, alternatively, an SSD stores data in memory chips that, unlike RAM, are nonvolatile, don't depend on having constant power and won't lose data once the power is turned off.

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 of RAM to run Photoshop CC 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.

DRAM Memory Cell: Though SRAM is very fast, but it is expensive because of its every cell requires several transistors. Relatively less expensive RAM is DRAM, due to the use of one transistor and one capacitor in each cell, as shown in the below figure., where C is the capacitor and T is the transistor. Information is stored in a DRAM cell in the form of a charge on a capacitor and this charge needs to be periodically recharged.
For storing information in this cell, transistor T is turned on and an appropriate voltage is applied to the bit line. This causes a known amount of charge to be stored in the capacitor. After the transistor is turned off, due to the property of the capacitor, it starts to discharge. Hence, the information stored in the cell can be read correctly only if it is read before the charge on the capacitors drops below some threshold value.

Types of DRAM

There are mainly 5 types of DRAM:

1. Asynchronous DRAM (ADRAM): The DRAM described above is the asynchronous type DRAM. The timing of the memory device is controlled asynchronously. A specialized memory controller circuit generates the necessary control signals to control the timing. The CPU must take into account the delay in the response of the memory.
2. Synchronous DRAM (SDRAM): These RAM chips’ access speed is directly synchronized with the CPU’s clock. For this, the memory chips remain ready for operation when the CPU expects them to be ready. These memories operate at the CPU-memory bus without imposing wait states. SDRAM is commercially available as modules incorporating multiple SDRAM chips and forming the required capacity for the modules.
3. Double-Data-Rate SDRAM (DDR SDRAM): This faster version of SDRAM performs its operations on both edges of the clock signal; whereas a standard SDRAM performs its operations on the rising edge of the clock signal. Since they transfer data on both edges of the clock, the data transfer rate is doubled. To access the data at high rate, the memory cells are organized into two groups. Each group is accessed separately.
4. Rambus DRAM (RDRAM): The RDRAM provides a very high data transfer rate over a narrow CPU-memory bus. It uses various speedup mechanisms, like synchronous memory interface, caching inside the DRAM chips and very fast signal timing. The Rambus data bus width is 8 or 9 bits.
5. Cache DRAM (CDRAM): This memory is a special type DRAM memory with an on-chip cache memory (SRAM) that acts as a high-speed buffer for the main DRAM.

 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.


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.

How important is RAM?

RAM is extremely important. Too little can lead to sluggish performance, although

smaller devices like tablets and

smartphones don't need as much as high end gaming desktops. However, installing massive amounts or using the highest MHz rating doesn't mean your device will run blazingly fast. Remember, RAM is only part of the overall equation.

Having enough RAM does matter, however, and having RAM that isn't bargain basement slow is a good idea too, especially for complicated image or video editing tasks and playing games that are CPU-limited.
But when it comes to improving your system’s overall performance, you need to consider the costs involved. A faster CPU or graphics card will typically make a bigger impact on your system’s overall speed than faster memory, though some CPUs, like AMD’s Ryzen line, do benefit more than others from faster memory. Upgrading from a hard drive to an SSD is also a big step if you haven’t taken it yet. The move to an SSD speeds up the slowest storage component on your system by a huge margin and contributes massively to making it feel more snappy.

As with any computing device, the slowest component typically limits performance, so slow memory can hold you back if it’s the worst part of your configuration. Unless you’re doing anything particularly intensive, just make sure you have a little more than what you need and that it’s not the worst available.

If you want something more powerful, there is a wide array of configurations of speed, size, and latency for you to choose.
Some even have RGB LED lighting, too,