Difference Between SIMM and DIMM

The SIMM and DIMM memory modules were invented to eliminate the older DIP (Dual Inline Package) chips. The DIP chips were delicate, and it is harder to install them as they needed to be poked in the socket. The pins of the chip are easily misaligned in the socket and tend to bend. So, when these chips are removed from the sockets, they require to be straightened which can result in the damaging of the chips and make it unusable. Then the SIMM and DIMM modules were devised which does not need to be penetrated and are surface mounted.

The crucial difference between SIMM and DIMM is that at a time SIMM have only one usable side due to having just one set of the connector while DIMM have different signal pins at each side which are usable and does not rely on the other side. The number of pins have also been increased in the DIMM as compared to SIMM.

Content: SIMM Vs DIMM

1. 1. Comparison Chart
   2. Definition
   3. Key Differences
   4. Conclusion

Comparison Chart

Basis for comparison	SIMM	DIMM
Basic	Pins present in either side are connected.	DIMM pins are independent.
Channel	32 bit	64 bit
Power consumption	5 volts	3.3 volts
Storage provided	4MB to 64 MB	32MB to 1 GB
Applications	486 CPU and early Pentium computers use SIMM.	Modern Pentium PCs are enabled with DIMM modules.

Definition of SIMM

SIMM (Single In-Line Memory Modules) is the tiny circuit boards having edge connectors where the RAM chips are placed. There are slots available on the motherboard for inserting these SIMMs. The SIMM connectors and the slot located on the motherboard are made up of either of the metal – gold or tin. In case the SIMM connector is of gold then the slot connector should be of gold only and not be of other metal. The metal connectors present at each side of bottom edges works effectively through the card, and just one set is of connectors are functional at a time.

Types of SIMM

There are two variants of the SIMM, one with 30 pins and other with 72 pins.

• 30 pins SIMM contain an address width of 8 bits and 1MB or 4 MB of RAM. Therefore, the data it can transfer from the memory bus at a time is 8 bits. Later hardware of 30 pins SIMM contains parity bit for the error detection which makes the address width of 9 bits. To ensure the proper installation of the SIMM, it has a notch on the bottom left.
• 72 pins SIMM can have an address width of 32 bits or 36 bits including parity bits. Each byte is allotted a parity bits (for 32 data bits 4 bits are for parity). The amount of RAM memory it has can be 4, 8, 16, 32, or 64 MB. It is notched at the side and centre of the module.

Definition of DIMM

DIMM (Dual In-Line Memory Module) also has metal connectors similar to SIMM, but either of the sides of the connector does not rely on the other. Advanced motherboards use 168, 184, 240 pin DIMMs. It consumes 3.3 volts of power and can store from 32 MB up to 1GB of memory.

Types of DIMM

• 168 pin DIMM structure is different from the SIMM because it has tiny notches along the rows of the pins at the bottom of the module.
• 184 and 240 pin DIMMs is provided with only one notch at the different position to prevent the improper placement of the DIMM in the socket.

Conclusion

After DIP chips, a technology was needed that can be easily removable and soldered. This gave rise to SIMM and DIMM modules which are soldered and easily manageable. However, among SIMM and DIMM, DIMM provides large address width (memory) relative to SIMM and consumes less power.