Before understanding DIMM, it is good to have information regarding RAMs and their accessories and how they operate. A RAM is a chip made up of several electronic elements that store the temporary working data of your system which can be read and written. RAM requires an electric supply for functioning, hence when the system is turned off, all data from RAM vanishes. It is mounted on the motherboard.
The RAM chips are not individually mounted on the motherboard because of less capacity, hence in earlier times, several chips used to be soldered together and converted into “modules”(integrated circuit boards) and these modules were mounted over motherboard using “pins”(also known as connectors).
Types of Modules
There are two types of modules in a RAM:
1. Single In-line Memory Module (SIMM)
In the case of SIMM, the connectors are only present on the single side of the module and are shorted together. SIMMs are always used in matched-pairs. The maximum data storage offered by SIMM is 32-bit/cycle and voltage consumption is 5 volts.
2. Dual In-line Memory Module (DIMM)
As technology evolved, SIMM became obsolete and was replaced by DIMM. DIMM has the row of connectors on both the sides(front and back) of the module and connectors are independent. This resulted in twice the capacity of DIMM with the same quantity of RAM hence supporting the 64-bit processors. While two SIMM sticks would be used in parallel for 64-bit data width (which is a disadvantage!). The voltage consumption of DIMM is 3.3 volts which are comparatively lower. It is not backward compatible i.e it cannot be used on motherboards having SIMM slots. It is easier to replace damaged or corrupted RAM piece on DIMM.
This proves that DIMM clearly outperforms SIMM in speed, latency, and power consumption. DIMM is generally available in 168, 184, 214 or 244 pins.
Classification of DIMM
DIMM can be classified on the basis of buffer size and type of RAM:
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DIMM classification based on buffer size:
- Unbuffered DIMM (UDIMM): The system directly reads/writes from/to memory chip without validation hence increasing the electrical load on the motherboard but are very faster.
- Registered DIMM (RDIMM): uses register that buffers signals, hence increasing clock cycle but are more reliable.
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DIMM classification based on the type of RAM:
- SDRAM (synchronous dynamic RAM) DIMM: It was the first dynamic RAM to sync with the system clock. The refresh rate was much lower due to re-accessing data after the rising half cycle.
- SDR(single data rate) DIMM: single data rate means the packet of data is only accessed once per clock cycle. Serial data can be read via the serial data pins on the DIMM which enables the motherboard to autoconfigure to the exact type of DIMM installed.
- DDR(double data rate) DIMM: Data packet is accessed twice each clock cycle. DDR DIMMs also use two notches on each side to enable compatibility with both low- and high-profile latched sockets.
- DDR2 DIMM: The key difference between DDR and DDR2 is that in DDR2 the bus is clocked at twice the speed of the memory cells, so data can be transferred four times faster per memory cell cycle.
How to Select Proper DIMM?
DIMM sizes vary from micro ATX to standard motherboards so no. of pins is an important factor. While purchasing a RAM stick, ratings are like 16 GB RAM can be 1X16GB(1 DIMM and 16 GB RAM each), 2X8GB(2 DIMM and 8 GB RAM each) or 4X4GB(4 DIMM and 4 GB RAM each). Operating frequency and maximum overclocking frequency should also be taken into consideration.
Advantages of DIMM Slots
- When comparing DIMM slots to SIMMs, the size of the data channel doubles because DIMM slots are known to contain distinct contacts on each side of the circuit board.
- Control signals and addresses from the CPU are buffered by DIMM. This buffering results in a notable decrease in memory usage.
- The dual-channel architecture allows the CPU to access memory on each DIMM independently.
- In addition to dual channels, there are triple and quad channels on the market that are employed for particular use cases.
- By supporting interleaving capabilities, these multi-channel DIMMs help to lower memory latency issues.
- The spreading of data across memory modules in alternating patterns is referred to as interleaving. Consequently, the CPU doesn’t have to wait for modules to finish operating in order to continue reading these data patterns sequentially from memory.
Difference Between DIMM and SIMM
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DIMM |
SIMM |
|---|---|
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Dual In-Line Memory Module is abbreviated as DIMM |
The acronym for Single In-Line Memory Module is SIMM. |
|
This memory module’s pins are independent |
This memory module’s pins, which are connected on each side. |
|
The power consumption of the Dual In-Line memory module is just 3.3 volts |
In contrast, a single in-line memory module needs five volts to operate. |
|
DIMMs offer 32 MB to 1 GB of storage |
SIMM offers 4 MB to 64 MB of storage |
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The performance of DIMM is good in comparison to SIMM. |
Its performance is low in comparison to DIMM. |
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DIMMs have two notches in them |
There is only one notch in SIMMS. |
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A 64-bit channel is supported by the DIMM memory module for data transmission |
A 32-bit channel is supported by the SIMM memory module for data transmission. |
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This memory module is used in Pentium computers nowadays |
Both 486 CPU and early Pentium systems use this memory module. |
Frequently Asked Question on DIMM – FAQs
What is DIMM?
Dual in-line Memory Module is shortened to DIMM. It is also a computer memory stick, as it is widely called. It installs in the motherboard’s memory cells. It is a module that is utilised by printers, laptops, and personal computers (PCs).
What is SIMM?
In the case of SIMM, the connectors are only present on the single side of the module and are shorted together. SIMMs are always used in matched-pairs. The maximum data storage offered by SIMM is 32-bit/cycle and voltage consumption is 5 volts.
What is the purpose of the heat spreader on DIMMs?
Heat spreaders can make the difference between a DIMM that functions (for a while) and one that doesn’t by keeping those chips that are operating outside of specification a few degrees colder.
What is ECC?
Can DIMMs be used in laptops?
Typically, desktop PCs, laptops, printers, and other devices use DIMMs. A 72-pin connector is needed for a SIMM (single in-line memory module), which normally provides a 32 data bit (36 bits counting parity bits) access to the computer.Error Correcting Code is a kind of computer data storage that detects and fixes n-bit data corruption in memory using an error correction code (ECC).
Can DIMMs be used in laptops?
Typically, desktop PCs, laptops, printers, and other devices use DIMMs. A 72-pin connector is needed for a SIMM (single in-line memory module), which normally provides a 32 data bit (36 bits counting parity bits) access to the computer.