14 Differences Between DIMM & SIMM

By Dominic Chooper on October 05, 2022

Single In-line Memory Modules and Dual In-line Memory Modules, which are commonly referred as SIMMs and DIMMs respectively, serve the same purpose but in a different way.

If you want to know about all the differentiating aspects between these two particular memory modules, this is perhaps the best article that you have chanced across.

You will find all the major differences between them and which one of them is more important.


The 14 Differences Between DIMM and SIMM


1. Acronyms

DIMM is the short form of Dual In-Line Memory Module while SIMM is the short for Single In-Line Memory Module.

The difference in their naming is based on the way the memory is packaged.

2. Year of Release

The DIMMs are considered to be the upgrade of SIMM and have been available since the 1990s.

On the other hand, historically, the SIMMs was created by James J. Parker in 1982 at Zenith Microcircuits. The patent for it was however granted to the Wang Laboratories in April 1987.

3. Age

Based on the respective date of release, the DIMM is a relatively newer technology as compared to the SIMMs and is considered to be their upgraded successor.

On the other hand, the SIMM is a comparatively older technology and is considered to be the predecessor of DIMM.

4. Electrical Connectors

The DIMMs typically come with separate electrical connectors on its two sides. There are ideally two notches in these particular memory modules.

On the other hand, the electrical connectors of the SIMMs are identical on the two sides. There is typically a single notch present in these memory modules.

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5. Data Path Size

The design of the DIMMs allows a single card to support a 64-bit data path. You will need to use DIMM in pairs only if there are any multi-channels requirements.

On the other hand, the SIMMs have a 32-bit data path on a single card. This means that you will need to use two similar pairs of SIMMs to support a 64-bit bus.

6. Efficiency

The good thing about the DIMMs is that there is no additional overhead due to parallel processing of the memory.

On the other hand, the paired SIMMs will enlarge the bus size but along with that it will also increase the overhead due to the fact that the processor will normally access the memory cards in parallel.

7. Pins

Most commonly the number of pins in the DIMMs is 168 but these memory modules may also support any combination ranging between 100 and 240 pins.

On the other hand, the SIMMs typically come with a much lower number of pins adding up to 72 only.

8. Size

Based on the pin configuration of the DIMMs, the size of these memory modules may range between 1.67 inches to 5.25 in length and 1 inch to 1.75 inches in width.

On the other hand, the usual size of the SIMMs is 4.25 inches in length and 1 inch in width.

9. Usage

DIMMs have become the memory module standard of today with the continual development that focuses on making faster chips and much enhanced management intelligence. That is why it is used in most modern Pentium computers, servers, and workstations.

On the other hand, the relatively low level of performance of the SIMMs made it easy for the DIMMs to replace them that are typically used in 486 CPU and early Pentium and other Intel computer systems.

10. Types

There are different types of DIMMs available such as SODIMMs, Unbuffered DIMMs or UDIMMs, Fully-buffered DIMMs or FBDIMMs, Registered DIMMs or RDIMMs, Load Reduced DIMMs or LR DIMMs, Micro DIMM, and more.

On the other hand, there are only two major variants of SIMMs available such as the 30-pin SIMMs and the 72-pin SIMMs.

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11. Power Consumption

The DIMMs consume much less power in comparison to the SIMM.

In fact, it is 3.3 volts for the DIMMs as opposed to 5 volts of power consumed by the SIMMs.

12. Storage Capacity

The DIMMs come with a much larger data storage capacity which can range anywhere between 32 MB and up to 1 GB, depending on the model.

On the other hand, the data storage capacity of the SIMMs is pretty low which is often between 4 MB and limited up to 64 MB only.

13. Performance

The performance and implementation of the DIMMs are quite good due to the design and the independent pins.

On the other hand, the implementation and performance of the SIMMs are not as good as the DIMMs mainly due to the connected pins and lower channel width.

14. Installation

The DIMMs are usually installed one at a time while, in comparison, the SIMMs are installed in pairs at a time.

Which One is Better to Use – DIMM or SIMM?

As you can see from the above list of differences, DIMMs are much faster in transferring data as compared to the SIMMs and also come with some greater capabilities.

Also, SIMM is an outdated technology as compared to the DIMM.

These are strong points enough for the DIMMs to replace the SIMMS. In such a context, you may consider the DIMMs to be better than the SIMMs.

There are several advantages of using a DIMM as well, which also makes it a much better option than SIMM.

Some of the advantages of using DIMMs are:

There are also triple-channels and quad-channels memory modules available for high-end use along with 6-channel and 8-channel memory modules that are used in the high-end servers.

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The larger data width allows even a single DIMM to transfer double the data than a SIMM more quickly.

Better memory technologies such as interleaving lowers latency in the multi-channel DIMMs because it spreads the data across the memory module in an alternating pattern.

Installed on the motherboard, the DIMM typically stores every data bit in distinct memory cells.

This helps the CPU to access the data pattern sequentially without having to wait for one module to be filled before accessing the following one.

However, the DIMMs are not backwards compatible with the SIMMs.

This means that you simply cannot upgrade the memory modules.

If you want to switch from SIMM to DIMM, you will have to replace the motherboard on the whole.

At times, this may even mean replacing the processor. That is why switching to DIMM is never quick and easy.

Still, the DIMMs are dominant today to the extent that it is not required to identify whether or not the memory module installed in your computer is a DIMM, because it is.

Ideally, there is no replacement as of now to the DIMMs and it is considered to be probably the best memory module for the foreseeable future.

Therefore, with all that said, the DIMMs surely have a significant edge over the SIMMs in this modern computing world.


To wrap it up, this article with the detailed differences between a Dual In-Line Memory Module and a Single In-line Memory Module must have surely helped you to gain more knowledge about them and know why the SIMM is replaced by the DIMM.