What is RAM and its Types? (Everything You Need to Know!)

What is RAM?

RAM stands for Random Access Memory and it’s a volatile memory which means it requires power to keep information stored. Simply we can say that RAM is a short term memory that offers working space to your computer. This lies in an internal memory category that stores data temporarily.

Due to directly accessible by CPU(Central Processing Unit) a RAM provides the fastest access to the data when the computer is running. As a volatile memory, it will lose temporarily stored data in that condition when your computer is shut down.

RAM comes in different types and dissimilar memory sizes like 4 GB, 8 GB, or 16 GB, etc. RAM space is measured in MB or GB and speed is measured in MHz or GHz.

Types of RAM (Random Access Memory)

SRAM (Static Random Access Memory)

SRAM Stands for static RAM and is built by using transistors. Four to six transistor memory cell is used to store data. It stores less amount of data because it is comprised of complex internal circuitry.

SRAM is faster due to lower access time and is more expensive as compared to DRAM due to more usage of the transistors. Unlike DRAM which requires a periodic refresh, SRAM keeps the data stored as long as the power is supplied.

Although due to the fastest response, it’s used in CPU cache(L1, L2, L3), CPU internal register, Hard drive buffer/cache, DACs.

DRAM (Dynamic Random Access Memory)

Stands for Dynamic RAM and it’s a type of volatile memory that is made up of transistors and capacitors. Within an integrated circuit, it stores a single bit of data in each capacitor. As well in this memory, every cell has a single transistor and capacitor.

It is less expensive as compared to static random access memory and also provides more memory. Although it offers excellent performance at a lower cost. DRAM offers slower access and used high power as compared to SRAM.

Moreover, it has also lose stored data as a volatile memory due to non-continuous power. And normally it is used in the system and video graphic memory.

Types of DRAM (Dynamic Random Access Memory)

SDRAM (Synchronous Dynamic Random Access Memory)

This memory type is a classification of DRAM (Dynamic Random Access Memory) and is faster than the DRAM. Due to directly Synchronous with the CPU’s clock, it supports up to 133MHz bus cycles and makes able to perform tasks more efficiently.

RDRAM (Rambus Dynamic Random Access Memory)

RDRAM is the fastest memory because its transfer speed can go up to 1GHz. Due to its efficiency, it mostly uses in the video games and graphics card but RDRAM also produces more heat.

Moreover, some motherboards have the ability to support RDRAM however most motherboards in the market cannot fully make use of its speed. Due to these reasons, it can’t normally use with computers as a short term memory.

DDR SDRAM or DDR1 (Double Data Rate Synchronous Dynamic Random Access Memory )

This memory works like as an SDRAM (Synchronous Dynamic Random Access Memory), DDR SDRAM is the latest version of SDRAM and the first generation of DDR memory. Its efficiency and higher bandwidth mean its bandwidth can go up to double.

The beauty of DDR SDRAM that it can process two reads and two write instructions per clock cycle. Hence working on both edges makes it faster instruction executioner.

The transfer rate of DDR first generation is 266 to 400 MT/s (Mega Transfer Per Second). This unit is measured bus and channel speeds. Along with efficient performance, its power consumption is high as compared to its next generation.

Types of DDR SDRAM(Double Data Rate Synchronous Dynamic Random Access Memory )

DDR1

Already explained above.

DDR2 SDRAM

Due to the great response of the first generation of DDR memory here comes the next generation with amazing improvements.

This memory is faster because it works at a higher clock speed. As well as, it process two read and write instruction like its first generation memory.

However, it consumes low power 1.8v (voltage) compared to DDR1 which consumes 2.5 – 2.6 voltage. Its internal clock speed (133~200MHz) is the same as DDR1 memory but the transfer rate is higher than 533 to 800 MT/s.

DDR3 SDRAM

Like the previous generation of DDR memory, this third generation of DDR memory works on a double data rate.

Due to more improvement, it works at a higher clock speed of 533 to 800 MHz and the transfer rate is 1066-1600 MT/s. It is available in two form factor DIMMs and SO-DIMMs.

Moreover, its evolutionary upgradations work on low voltage(1.35/1.5v) and 30% to 40% less consumption than DDR2.

DDR4 SDRAM

This is the latest 4^th generation and most efficient version of DDR memory. With greater memory capacity its data transfer rate is 2133-3200 MT/s and clock speed is 1066-1600MHz.

And in this memory, there are 4 bank groups that mean it can operate 4 different operations simultaneously.

With 16 internal memory banks, DDR4 offers 64GB maximum per memory module. DIMMs and SO-DIMMs are two form factors of this memory – first one use in desktop and the later is for laptops. Along with excellent performance, it runs on low voltage 1.2v.

DDR SDRAM	Internal Rate	Bus Clock (MHz)	Prefetch	Data Rate MT/s	Transfer Rate GB/s	Voltage
SDRAM	100-166	100-166	1n	100-166	0.8-1.3	3.3
DDR	133-200	133-200	2n	266-400	2.1-3.2	2.5/2.6
DDR2	133-200	266-400	4n	533-800	4.2-6.4	1.8
DDR3	133-200	533-800	8n	1066-1600	8.5-14.9	1.35/1.5
DDR4	133-200	1066-1600	8n	2133-3200	17-21.3	1.2

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