Building or Customizing a PC? Choose the Right Motherboard-Memory Combo!

Building or Customizing a PC? Choose the Right Motherboard-Memory Combo!
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If you’re looking for a new motherboard for your PC, you need to be very careful about the choice that you make. The same is true when purchasing new memory modules for a computer or laptop.

While purchasing a like-for-like replacement for a PC from Dell, HP or any of the other computer manufacturers is reasonably safe (although not always) adding a new motherboard as an upgrade can be littered with compatibility issues.

Along with the more obvious CPU and graphics card expansion slot compatibility is the small matter of purchasing the correct RAM modules for your new motherboard. You cannot expect existing RAM modules to run correctly with a new mainboard without checking that they are supported. In many cases, however, memory is upgraded at the same time: This is why motherboard-memory combo packs are available on PC component websites.

You don’t have to rely on these pre-packaged combos, however. There are plenty of websites where you can make your own choice of motherboard and find suitable RAM that can be used for optimum performance on the dollar.

Benefits of Making the Right Choice

Rather than looking at the benefits of making the right choice, let’s first look at what will happen if you make the wrong choice. Regardless of whether you purchase RAM modules and a new motherboard together or if you still plan on using older modules from an existing system, there is plenty of scope for something to go wrong.

At the positive end of the scale, you might end up with a working PC, but one that is slow and crashes often.

Conversely, you might have difficulty starting your PC, or even be unable to physically insert the memory, if the RAM modules don’t suit the motherboard.

The differences in RAM modules are considerable, despite appearances, and relate to their speed, the amount of power they need and the available bandwidth of the motherboard. While some RAM modules are backwards compatible, they will never reach their optimum speed when added to a slower, older motherboard.

Physical Differences Between Different Types of Memory

Differences Between Different Types of Memory

You should think of the different types of RAM - DDR, DDR2, DDR3 - as different “generations” of memory module. For instance, DDR2 SDRAM is twice as fast (with regard to clock rates and bandwidth) than the earlier DDR SDRAM

When selecting RAM modules for your motherboard, you should be aware that different memory types cannot be used on all motherboards.

Naturally you’re not going to confuse a laptop memory module with a full-sized desktop computer RAM component, but there are other differences. When inserting a new memory module, it is imperative that you get the component the right way around - this is because there is a notch around two-thirds of the way across the length of the RAM.

As you might have worked out, this forces you to insert the module in the right way, but not all RAM modules have the notch in the same place. You can see in the accompanying illustration that DDR, DDR2 and DDR3 modules all have the notch in different positions, and this is done to prevent the wrong modules being installed.

Sadly, it isn’t unheard of for inexperienced users to try to force in a memory module that looks as though it might fit, with the resulting damage to the RAM and the motherboard rendering each unusable.

Checking Online Motherboard Manuals

If you have identified a motherboard that you wish to use, you should check the manual for the component.

But how do you do this before purchasing the hardware?

Simple – find out the name of the manufacturer, visit their website and run a search for the manual. This will typically be found in the support section, and can be downloaded for you to read. Usually these manuals will require you to have Adobe Reader or some other PDF-format reader on your computer. Keep an eye out for something along the lines of a Compatible, Qualified or Approved Vendor RAM or Memory Vendor List as well, which gives more detailed information about parts recommended for use with the motherboard in question.

Motherboard manuals are usually split into several parts, the first featuring details on the specification, the second on the diagram and the various switches, plugs and connectors and the third on the BIOS configuration of the motherboard. You should be looking at all three sections, but particularly the first to find out what memory module types are compatible.

Browser-Based Tools

There are a couple of useful browser-based tools that you can use to match up a motherboard to suitable RAM.

The first place you should try is the Intel motherboard selector website. Although specifically designed to provide suggestions on motherboards, chipsets and optimal CPUs, the website also provides information on suitable memory types, for instance letting you sort mainboards by DDR2 compatibility.

Meanwhile is an excellent resource for finding the right memory for your motherboard, whether it is brand new, several years old or still sat inside a pre-built desktop or laptop computer. Most of the larger memory vendors offer similar tools on their website, so if there is a brand you like or a model you want to check out it is a good idea to check there.


Intel motherboard selector

Photograph provided by author.

Image credit: Wikimedia Commons/Jovianeye