The ABC’s Of PC and Laptop Memory

If you plan on replacing, upgrading, or installing new memory on your PC or laptop – you may be unsure of what kind of computer memory you need to invest in. With all of the types of computer memory available on the market, it is easy to get confused.

To help you when shopping for your next computer memory system, I have created the ABC’s of PC and laptop memory to help you determine what you need. I will also cover the different types of memory, which types of memory are ideal for your computer system, and how your desktop may require different types of memory than your laptop.

When you read the specs of each computer system you own, each computer will state how much Random Access Memory (RAM) it has. RAM is what is used to store and run instructions and information during processing. This memory can be found on the slots of your motherboard, in thin strips referred to as memory modules.

When looking at your green circuit board, the small gold strips are referred to as pins. Pins are what connects your memory modules to their slots on the motherboard of your computer system. Each memory module has a designated notch on the motherboard to ensure that information is carried to the correct module.

If you will be manually installing a memory board to your computer system, you must ensure that the motherboard is properly fitted or “seated” into the designated slot, to ensure a secure connection to the motherboard.

Keep in mind that dynamic random access (DRAM) is standard for desktops and notebooks, and single data rate (SDRAM) is used in computer systems older than 2002.

Double Data Rate Memory

Double data rate DDR SDRAM become an industry standard for computer memory in 2002. The invention of DDR truly revolutionized computer systems, in that it increased data transfer speed by twice as much as its predecessor, the SDR memory module. This is because DDR has the ability to simultaneously read data on the rising and falling edges of the clock signal.

DDR is available in a dual in-line memory module (DIMM). The dual in-line memory module has a multitude of memory segments (found in black), all of which are placed on your green circuit board. The gold pins connect the DIMM to the slot when properly installed on the motherboard.

The number of black memory segments on a DIMM can vary from computer system to computer system, depending on the type of computer memory you require. However, there are always 92 gold pins on each side of the DIMM—184 in total. A standard DIMM is approximately 5.25 inches long, but can vary in height to best meet your needs.

This type of computer memory is used for PCs and is available in a variety of different speeds. In order to install this computer memory system yourself, check your owner’s manual to ensure that you have the proper DIMM slots, and DDR enabled chipset to achieve speeds of: PC2100 DDR, PC2700 DDR or PC3200 DDR.

DDR2 For PCs – The Next Step In The Evolution Of Computer Memory Systems

As of 2004 “follow-on” technology referred to as DDR2 hit the market. Again there was an increase in speed with this new system, which was able to achieve a bandwidth of up to 8.5 GB per second. To further enhance memory, DDR2 computer memory systems can be installed in pairs to create a dual channel mode.

In order to transmit data faster, DDR2 has 240 pins – which in turn means you must ensure that your PC has a 240 pin in the motherboard, as well as a DDR2 enabled chipset. If your PC does not meet these requirements, the DDR2 will not fit properly. If you are unsure what your computer system has, check your owner’s manual.

Notebook Memory Systems

When it comes to notebook computer memory systems, small outline dual in-line memory modules (SODIMM) are the standard. These memory modules come with 200 pins, and fit into the DDR or DDR2 slots – whichever your notebook has.

As with all computer memory systems, you must ensure that you have the proper enabled chipset. S0DIMMs are typically about 2.5 inches long, and 1.25 inches tall. The notch on your S0DIMM, can be found on the left-hand side of the module. Once again, check with your owner’s manual to ensure that your notebook is properly enabled.

The Introduction Of The Fastest Memory Model To Date—DDR3


As of 2007 the DDR3 computer memory system became available. The primary differences between this system and its predecessor, is that it is once again faster – having the ability to transfer data up to 12.8 GB per second. On top of that the DDR3 computer memory system is more energy efficient because it is able to operate with a lower voltage. The DDR3 traditionally works with memory modules in banks of 1-3. Having dual or triple channel modes allows for increased memory and performance compared to that of a single module.


As a general rule of thumb, each motherboard is built for a specific type of computer memory system. This means you are not able to install or mix-and-match different types of memory systems because they will not fit into the sockets of your motherboard.

The information above is an excellent introduction to the most common types of computer memory, for the most common computer systems. This information can be used to help you determine which ways you can improve and upgrade your computer memory.

For additional questions about your specific computers memory system you can contact your manufacturer directly, or seek the expertise of a professional at your local memory retailer.

Until next time……


Selma is a passionate creator who continues to branch out and explore new artistic endeavors. She is a Web Developer and Internet Marketer. She was an early online entrepreneur, who launched her web design company in 1996, and she has been working solely online since 2004. She is a proud mom of 5, who calls the picturesque Iceland home. Her versatile interests also include Songwriting, Electronics Technician, and she is a published Children’s Book Author.

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4 thoughts on “The ABC’s Of PC and Laptop Memory

  1. I want to share as well how to check your ram version, you can use CPUID it’s a free software that scans your hardware and its version so it can check whether your motherboard can support specific ram version. I have the DD3 but I need to buy another one because my computer needs it to run faster.

    • Hi Jay and thanks for your comment.
      Yes, using a software like CUPID is a quick and easy way to generate a list of hardware information like your PC’s memory, cache, graphics, and SPD.


  2. I have to be honest that I got dizzy when reading RAM because I am not a techy person but thank you for making it so detailed that I was able to understand it. Keep on adding more post like this because it is interesting and the information that I’ve learned is amazing.