How to Build a PC - Motherboard Selection

In our previous entry we discussed the considerations for selecting your CPU. If your CPU is the “brain” of the system, the motherboard is the “heart,” and that is what we will be discussing in this arcticle.

Motherboards have evolved quite a bit over their lifespan. In the early days, on up to the mid 90’s motherboards had limited built in devices and relied heavily on add-in cards via expansion slots. As time went on, more and more of the functions of these add-in cards became integrated directly into the motherboard, such as the storage, network and audio controllers that we find built into modern motherboards. For most people, the built in functionality of these devices are more than sufficient for their needs, however you can still find standalone add-in cards for things like LAN, storage, and audio (among other things) which offer advanced functionality over the built in devices. In more recent times, we have seen many functions of the motherboard migrate to the CPU, such as cache memory, and many functions of the north bridge area of the chipset, including the memory controller, and even GPU (graphics processing unit) with some CPUs. Corsair actually started out selling CPU Cache memory modules, you can see an old magazine advertisement for them below.

When choosing your motherboard, the first and most important thing to figure out is what type of CPU socket your CPU requires. Once you have this information you need to find out which chipsets support this socket. In many cases there may only be a single chipset available which will support any given CPU socket. However, over time more advanced chipsets may be released which will retain the same type of CPU socket as a previous generation chipset, while adding features or improving upon existing ones. Below you can find some examples of current generation CPU sockets (Intel LGA 2011-3, Intel LGA 1150, and AMD AM3+).

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When talking about motherboards and chipsets, it is easy to confuse the two terms, so let me explain what I mean when I use the terms.

Motherboard: The motherboard consists of all the integrated circuits and devices that are permanently attached to the mainboard, which includes the chipset.

Chipset: Chipsets are specific groups of integrated circuits which allow for the communication between the major components of the motherboard, most importantly the CPU, memory, and peripheral devices.

In modern consumer level motherboards, most chipsets are initially designed by AMD or Intel, for use with their respective CPUs. These chipsets designed by CPU manufacturers are called reference versions of the chipset. Most motherboard manufacturers will use these reference versions of a chipset as a foundation for designing their own motherboards. While some motherboards will use a pretty standard iteration of the reference design of a chipset, some motherboard manufactures will add features to the reference design, adjust the layout, or make the existing features more robust with the help of their own engineering teams. This is why you can find some motherboards available for $99 and others beyond $300, even though they may support the same CPU socket, and chipset.

Let’s talk about some of the ways in which motherboard manufacturers differentiate their motherboards from both the reference designs, and their competitors.

Connectivity

One of the most obvious ways in which motherboards differ is the amount and type of connectors available on the rear I/O panel, as wells as the amount of internal headers on the motherboard. Higher end boards tend to offer better connectivity than others.  Here is a list of some of the typical connectors you might find in the rear I/O panel of a motherboard:

• USB 2.0
• USB 3.0
• HDMI and or DVI (with chipsets that support onboard video)
• eSATA
• Firewire (IEEE 1394)
• Thunderbolt
• PS2 (Legacy)
• Optical (audio)
• 3.5mm Audio ports
• Network (LAN)
• CMOS reset

Motherboards may have some or all of these connectors in varying amounts, so it is important to determine how you plan to use the system, in order to figure out what ports you will need, and in what quantity. For example, if you doubt you will be using any Thunderbolt devices, you probably do not need to get that super high end board that comes with a Thunderbolt port, unless of course it has something else you need.

When I mention internal motherboard headers, I am talking about the internal connectivity of the motherboard. You will find varying amounts of case fan headers, USB2.0 and 3.0 internal headers and SATA ports, among other things. On higher end boards you may have some onboard controls which allow for power, reset, CMOS clear and sometimes more, right from the motherboard itself. Below you will find an example of a high end motherboard from Gigabyte that has quite a few buttons and switches right on the motherboard which offer advanced control.

Most of these rear I/O and internal connectors can be expanded upon through the use of PCI expansion cards; however it is still something that you should take into account when searching for the ideal board for your system.

Form Factor

Motherboards come in a few different standardized shapes and sizes, called “form factors.” The most common form factors are ATX, micro ATX (mATX), EATX and mini-ITX, however there are also some more exotic form factors out there. Below you can see how these different form factors compare in size with these ROG Series motherboards from Asus.

Larger motherboards tend to have more features and options, along with better connectivity, at the cost of their larger size. With modern motherboards having many of the critical elements built right into the motherboard and CPU, many people do not need the expansion capabilities of larger motherboards, and would rather build a smaller more portable system. You will need to determine which form factor of motherboard you will want to base your build around before you move on to picking out a chassis.

Quality of materials

High end motherboards will often advertise the use of high quality components such as capacitors and transistors which are made from premium materials that withstand heat better than a typical component found on a lower grade motherboard. This may not mean a whole lot to someone who is building their grandma a machine for internet access and email, but for anyone who is interested in overclocking, and tweaking your PC, you will be able to push your hardware a lot harder if it’s built with higher quality materials, not to mention it will potentially last a lot longer as well.

Cooling features

Cooling is another way in which manufacturers are able to differentiate their motherboards from eachother. Higher end motherboards tend to have larger, more elaborate heat sinks, some with heat pipes and/or fans to help to cool down the hottest parts of the motherboard. Some manufacturers will also add extra temperature sensors and provide you with expanded cooling and monitoring options within the BIOS.

Aesthetics

A popular trend that motherboard manufactures picked up on is that hardware enthusiasts like to color coordinate their builds. Because of this you will find that different manufacturers tend to use different color themes on their boards. If you are going to want to show off your build, you may want to decide on a specific color scheme based around your motherboard. Below, you can find some examples from Gigabyte, MSI, and AsRock.

Performance

The quality of materials and cooling features can both be good indicators of the potential performance of a motherboard, but nothing beats good ol’ real world testing! Just like I mentioned with CPUs in the “How to select a CPU” section of this guide, it’s a good idea to look around and see how certain boards are performing out in “the wild.” Overclocking forums are a great place to check out enthusiast’s results, as well as established enthusiast hardware review sites that will often compare the latest motherboards.

PCIe Slot configuration and graphics performance

The PCIe slots on a board are where you will plug in your graphics card(s) as well as any other expansion cards, such as sound cards, wireless network cards, RAID controller cards, etc. In a typical system many people will only use a single one of these slots for a discrete (or standalone) graphics card. If you intend to add more cards than just a single GPU, then you will need to plan out where you will install your cards and make sure you have enough room. Many graphics cards take up 2 PCIe slots, and some even take up 3 slots, so keep this in mind when selecting your motherboard.

Another concern is the speed of the PCIe slots. Regular expansion cards that do not require a lot of bandwidth may require PCIe x1, or PCIE x4 slots, while most modern graphics cards are going to need the extra bandwidth found in PCIe x8 and PCIe x16 slots. Most enthusiast grade boards will have at least one or two slots rated for PCIe x16, but keep in mind that many boards with PCIe slots capable of x16 will downgrade to x8 when using multiple graphics cards. If this is a concern, you should check the specifications of the motherboard very closely. To get the absolute most out of a high end graphics card, x16 is what you want, however boards with dual active x16 PCIe lanes tend to be somewhat rare and can be very expensive. The return on the investment of a true dual x16 board may not be worth the extra 1%-5% gain in graphics performance that you can expect.

What factors are the most important to consider when selecting a motherboard?

Now that we have discussed some of the most important factors to consider when choosing a motherboard, I will recommend the order in which you should consider these factors. Keep in mind that this is only my suggestion, and depending on your specific purpose for building the system, you may rank these factors differently.

CPU socket, Chipset, Form Factor

The first factor will always be choosing the correct CPU socket and chipset to ensure that your motherboard is compatible with your CPU. Your next concern should be the type of form factor the motherboard was designed to meet, since it will dictate how large your case will ultimately be, and how much expansion it will support.

Performance, Cooling, Quality of Components, PCIE Configuration

Once you have figured out which CPU socket, chipset and form factor you need, you will need to decide how much you want to invest into the performance characteristics of your motherboard. For a typical gaming system, you probably do not need an incredibly high performance motherboard with all the bells and whistles. However if you intend to use multiple graphics cards, or think you may want to play around with some overclocking, then your system is going to run a bit hotter and it may be a good idea to get a board with higher quality components, and improved cooling characteristics. If you plan on running multiple GPUs, or if you know you will have some PCI expansion cards, then you will need to pay close attention to the PCI configuration of the board as well. You will need to worry about both the speed that the slots support, and their physical location on the motherboard, to ensure you have enough space to fit all your cards together.

Connectivity and Aesthetics

The least important things to worry about are likely going to be connectivity and the aesthetic differences. While connectivity is important, it may not make or break your decision since using expansion cards can often resolve any connectivity issues. Aesthetics will not change your compatibility, or performance, so this is purely a personal judgment call.

Next Steps

With these factors in mind, you should have what you need in order to pick out your ideal motherboard. In our next article we will be discussing how to pick out the right memory to go with your CPU and motherboard. Stay tuned!