Difference Between SIMM and DIMM

The older method to store and install memory chips was difficult and harder. Earlier, DIPs (Dual Inline Package) were used as storage modules in computers. But these were harder to in-built in the computers as they are delicate and have to be installed in the sockets.

Sometimes due to mishandling, the pins of the DIP chip are also misaligned, which damages it and unusable. Therefore, SIMM and DIMM were invented as the alternative.


The main difference between SIMM and DIMM is that SIMM has pins installed on their sides, while in DIMM, the pins are independent. SIMM provides a maximum of 32-bit of channel for the data transfer while DIMM allows 64-bit for the data transfer through them. The power consumption of them is also different SIMM uses 5 volts while DIMM uses 3.3 volts.


SIMM in the expanded form is known as Single in-built Memory. They were used in computers from the year 1980-the 1990s. Invented by James J. Parker in the year 1982. The SIMM chips get their standard mark from JEDEC Solid State Technology Association. They are distinguished in further two types 30 pins SIMM and 72 pins SIMM.

DIMM in the expanded form is known as Dual in-line Memory. It is also known as the RAM stick. It is used in motherboards of modern computers. It entered the market to replace the use of SIMM after the demand for Intel P5-based Pentium processor. The main two types of DIMMs are 168 pin DIMM and 184 and 240 pins DIMM.

Comparison Table Between SIMM and DIMM

Parameters of ComparisonSIMMDIMM
Full-FormSingle in-line MemoryDual in-line Memory
BasicThe pins are present on the sides.The pins present are independent.
Channel 32 bit64 bit
Power It uses around 5 volts.It uses around 3.3 volts.
Storage It provides a capacity of 4 Mb to 64 Mb.It provides a capacity of 32 Mb to 1 Gb.
ApplicationEarly Pentium computers and 486 CPU uses SIMM in them.Pentium Modern PC’s uses DIMM in them.

What is SIMM?

SIMM is stated as Single in-built Memory. It consists of random-access memory, which is used in computers from the 1980s to the late 1990s. SIMM is a module type. 

SIMM was invented by James J. Parker in the year 1982 at Zenith Microcircuits. After their invention, Wang Laboratories became their first customer and filed for the patent, and they were also granted the patent in the year 1987, the month of April. 

The standardization of these SIMM chips was under the JEDEC Solid State Technology Association JESD-21C standard. The aim behind the invention of SIMM was to reduce the number of Dual In-line Package chips used in the motherboards like – 8088-based PC, XT, and AT.

SIMMs are installed on the surface, and the pins and the SIMM connector are supposed to be of the same metal. They are only made up of gold and tin. The uneven metal should not be used for them. 

SIMM can be distinguished further in two types which are as follows:

  1. 30 pins SIMM – It has an address width of about 8-bit and has a capacity of 1 MB or 4 MB RAM. For the proper and safe installation of the chip, there is a notch present at the bottom of it. 
  2. 72 pins SIMM – It has an address width of about 32-bits or 36-bits. For the proper installation, the notch is present at the side and in the center.

What is DIMM?

DIMM is stated as Dual in-line memory. It is also known as a RAM stick. DIMM comprises of series of dynamic random-access memory meaning it stores a single bit of data in its memory which contains both transistor and capacitor with monolithic integrated circuits.

DIMM came to existence when they started to replace SIMM (Single in-line Memory) after the invention of the Intel P5-based Pentium processors module in the market. 

DIMM comes with the advantage of less power consumption. That is, it uses only 3.3 volts compared to SIMM. They also provide a large storage capacity of about 32 MB to 1 GB.

The pins which are present on the chip are independent. The variants which support slots of DIMMs in the market are – DDR, DDR2, DDR3, DDR4, and DDR5 RAM. DIMM is divided mainly into two types which are as follows – 

  1. 168 pin DIMM – The structure of the 168 pin DIMM is different compared to SIMM as they consist of tiny notches along the row of the pins, which is present at the bottom of the module. 
  2. 184 and 240 pins DIMM – It consists of only one notch but present at a different position so that it helps in preventing the uneven placement of DIMM in the socket. 

The DIMM or RAM sticks are now used in many advanced motherboards as they are surface mounted. Thus, they are present in personal computers, or at the workplace, printers, etc.

Main Differences Between SIMM and DIMM

  1. The full form of SIMM is Single in-line Memory, while the full form of DIMM is Dual in-line Memory.
  2. The pins present in SIMM are present at the sides, while the pins present in DIMM are present independently.
  3. The channel of SIMM is 32 bit, while the channel of DIMM is 64 bit.
  4. The power consumed by SIMM is about 5 volts, while DIMM uses about 3.3 volts of power.
  5. The storage provided by the SIMM ranges between 4 Mb to 64 Mb, while the storage of DIMM ranges between 32 Mb to 1 GB.
  6. SIMM is used in early Pentium computers and the 486 CPU, whereas DIMM is used in modern Pentium Computers. 
Difference Between SIMM and DIMM


After the invention of SIMM and DIMM, they revolutionized capacity and easy management. The earlier used Dual In-line Package (DIP) chips were hard and difficult to manage. The installation of these chips was also difficult and was said to handle with care as if they are misaligned once, then they became unusable for any further purpose.

But in contrast, SIMM and DIMM came for the rescue of motherboards. Although with time, SIMM has also become outdated while DIMM is still used in new technologies. The capacity of storage is large. The power consumption is low. They are easily installed on the surface, making it the right economical choice.


  1. https://ieeexplore.ieee.org/abstract/document/1262788
  2. https://ieeexplore.ieee.org/abstract/document/471053
  3. https://digital-library.theiet.org/content/journals/10.1049/iet-cta.2009.0583
  4. https://ieeexplore.ieee.org/abstract/document/776247
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