What is RAM? | Different Types of RAM Explained

Most everyone is familiar with the word RAM. Because when we buy devices like Smart Phone, tablets, and Computers, we use the word RAM casually. But what is RAM and do you know about the types of RAM?

That’s what this post is about. Let me explain various information about RAM simply for you to understand. Through this post, you will have a better understanding of RAM.

Before learning about RAM let’s look at the types of computer memory. Ok, let’s get started.

Types of Computer Memory

Computer memory is generally classified into two types. They are Internal Memory and External Memory.

Internal Memory: This is called the main memory of the computer. The main files and applications required by the computer are stored in the internal memory. Internal Memory communicates directly with the Central Processing Unit.

For example, both ROM and RAM memory belongs to the Internal Memory category.

External Memory: This is called Secondary Memory. It is used to store data and information permanently. This external memory can be either embedded or removable storage.

For example, Hard Disk or Solid State Disk, USB Flash Drive, Compact Disk, Floppy Disk, etc.

What is RAM?

RAM (Random Access Memory) is a hardware memory device that stores data for a short period of time. The data of the applications currently being used by the CPU is temporarily stored in this RAM memory. When we close those applications, the data stored temporarily in the RAM memory is also deleted.

Let me give an example to make it easier to understand. When you open Photoshop software on your computer, all its data on the hard drive is temporarily stored in the RAM memory. Then the CPU fetches the required data from the RAM memory. When you close Photoshop software, the data in RAM is also erased.

The computer can access the data in the RAM memory much faster than the data in the long-term storage device like HDD, or SSD. So RAM memory is important for the performance of a computer.

Different Types of RAM

RAM memory comes in different types. They are classified by factors like RAM memory performance, technology, and hardware.

Generally, there are two main types of RAM Memory, Static RAM (SRAM) and Dynamic RAM (DRAM).

Static RAM (SRAM)

Static RAM is memory made up of four to six transistors. It has the ability to store information until the computer is powered on. It should be updated from time to time.

Static RAM

SRAM has a fast operational capability. But it is expensive. So SRAM is used as Cache Memory for the CPU.

Dynamic RAM (DRAM)

Dynamic RAM is a memory made up of circuits consisting of a transistor and a capacitor. Each bit of data is stored in a capacitor inside the integrated circuit. Data must be updated every few milliseconds to keep it consistent. Otherwise, it loses the data stored in it.

Dynamic RAM

DRAM has less functionality compared to SRAM. However, DRAM memory is used in all modern computers because Dynamic RAM is cheaper and has a higher capacity.

Common Types of DRAM

There are a few types of DRAM. Let’s see what they are.


An extension of SDRAM is Synchronous DRAM. It is a DRAM-type chip that has been widely used since the 1990s. It synchronizes Memory Speed with CPU Clock Speed. It helps in data connection between the main memory and CPU.


Rambus DRAM is an extension of RDRAM. Rambus is a company name. RDRAM was introduced by Rambus in 1999. Rambus DRAM is significantly faster than older models of Synchronous DRAM (SDRAM).

Typically, SDRAM can transfer data up to 133 MHz. But RDRAM can transfer data at 800 MHz.


An extension of DDR SDRAM is Double Data Rate SDRAM. It has the same features as SDRAM. But, it have twice data transfer frequency.

It is called Double Data Rate SDRAM because it doubles the transfer rate. This allows higher transfer rates and faster performance than previous RAM models.

Different Types of RAM

Different Types of RAM - Computer Memory

Generations of DDR SDRAM

Currently, DDR SDRAM is abbreviated as DDR RAM. So please note that DDR SDRAM and DDR RAM are the same.

DDR RAM comes in different generations depending on its speed and performance. You can find details about them.

1. DDR 1


In 2000, the DDR1 RAM type was introduced. Its transfer rate is between 2.1 to 3.2 GB/s. The voltage used by this type of RAM is 2.5/2.6. As it is a very old type of RAM, it is not commonly used nowadays.

2. DDR 2


DDR 2 RAM was introduced in the market in 2003. It is more efficient than the previous DDR 1. Its transfer rate is between 4.2 to 6.4 GB/s. 1.8 Voltage is consumed in this type of RAM. This is also an old type of RAM and is no longer used.

3. DDR 3


Released in 2007, DDR 3 RAM is faster and more efficient than DDR 2. The transfer rate of DDR 3 is 8.5 to 14.9 GB/s. This is twice as fast as DDR 2. Its power consumption rate is 1.35/1.5 Voltage. This type of Random Access Memory can be found in some older computers.

4. DDR 4


DDR 4 Generation RAM was released in 2014. Compared to all other types of RAM, its speed and performance are much higher. The Trasfer Rate of DDR 4 type RAM is 17 to 21.3 GB/s. Its power consumption rate is 1.2 Voltage. All computers in use today use DDR 4 type RAM.

5. DDR 5


DDR 5 is the latest and most efficient of the RAM types available today. In 2020 the world’s first DDR 5th Generation was released. Its Transfer Rate is 35 GB/s and Power Consumption is said to be 1.1 V.

It is also said that it cannot be used in existing motherboards, but only in specially designed motherboards.

DDR RAM GenerationsYear of LaunchData Rate (MT/s)Transfer Rate (GB/s)Voltage (V)
DDR 12000266 – 4002.1 – 3.22.5 / 2.6
DDR 22003533 – 8004.2 – 6.41.8
DDR 320071066 – 16008.5 – 14.91.35 – 1.5
DDR 420142133 – 320017 – 21.31.2
DDR 520203200 – 6400321.1


Above we know the different generations of RAM from DDR 1 to DDR 5. But what is LPDDR RAM? The question may arise for some people.

LPDDR stands for Low Power Dynamic Double Rate. This type of RAM consumes less power.

Generally, LPDDR RAM is designed for devices like Mobile, Tablet,s and Ultrabooks. Its operating speed is slightly compromised to save some energy.

Currently, some laptops also support this LPDDR RAM. LPDDR was first released in 2008. Then followed by LPDDR2, LPDDR3, LPDDR4, LPDDR4X and LPDDR5 generations.

A laptop with LPDDR memory will have a longer battery life than a laptop with DDR memory.

You can follow the Laptop Buying Guide to choose the best laptop for you.

GenerationsLaunch DateData Transfer Rate (MT/s)Voltage
LPDDR2008333 – 4001.2 V
LPDDR22010800 – 10661.2 V
LPDDR320121600 – 18661.2 V
LPDDR4201432001.1 V
LPDDR4X20173200 – 42670.6 V
LPDDR5202064000.5 V


In this post, we have learned about the different types of RAM Memory. Here is a summary of the above information:

  • A computer has two types of memory Internal Memory and External Memory. RAM comes in Internal Memory.
  • RAM stands for Random Access Memory
  • There are two main types of RAM memory, SRAM and DRAM.
  • An extension of SRAM is Static Random Access Memory. It consists of 4 to 6 transistors.
  • An extension of DRAM is Dynamic Access Memory. It consists of a transistor and a capacitor.
  • There are three types of DRAM namely SDRAM, RDRAM, and DDR SDRAM.
  • DDR SDRAM is a type of SDRAM memory.
  • DDR SDRAM is also called DDR RAM for short.
  • There are 5 generations of DDR RAM from DDR 1 to DDR 5.
  • LPDDR stands for Low Power Dynamic Random Access Memory.
  • LPDDR can be found in Smart Mobiles, Tablets, Ultrabooks, and some laptops.

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