Motherboard parts explained
In this article, we outline all the relevant motherboard parts and explain everything you need to know regarding their function
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Motherboards are as crucial to a PC’s operation as CPUs are, maybe even more so. Without a motherboard, your computer would be nothing more than an expensive paperweight. Budget or expensive, high-end or low-end, all motherboards aim to serve the same purpose. But what is a motherboard? And what do all its parts do? Good question, allow us to explain.
If you’re in the market for a new motherboard, we have a few ‘best of’ articles listed below to help you find a motherboard that’s right for you.
What is a motherboard?
Motherboards are arguably the most important component of your PC. A motherboard allows all your components to communicate with one another, such as your CPU, GPU, and RAM, all of these components would be rendered useless if you don’t have a motherboard to install them into.
It’s this communication that allows a computer to operate, if even one component isn’t pulling its weight, then the PC will not function properly and most likely fail altogether.
Besides ensuring all of your components communicate in perfect synergy, your motherboard also houses a chipset that controls PC I/O interactions. This is designed specifically to work with a certain CPU architecture, whether that be Intel or AMD’s respective architecture. For example, Z690 chipsets belong to Intel and X670 chipsets belong to AMD.
We’re operating under the assumption you have at least a slight understanding of what a motherboard is and how it works. So with that being said, let’s get into explaining the different parts of a motherboard.
Motherboard parts explained
Here are 16 of the most common and most important parts of a motherboard, below we will explain what they are and how they work. These parts are in no particular order.
CPU socket
A CPU socket is exactly what it says on the tin. The socket is located in the middle of the upper half of the motherboard. CPU sockets have what are called ‘lanes’ or ‘traces’ connected to them, although they themselves are a single connector between the CPU and motherboard. These connected lanes allow communication between the CPU and the rest of the components connected to the motherboard.
Sockets are usually square or slightly rectangular in recent years with the release of 12th Gen Alder Lake Intel CPUs, which themselves are slightly rectangular.
CPU sockets tend to come in two separate configurations in 2022, and those are LGA (land grid array) and PGA (pin grid array). Intel has been using LGA for years now, but with the introduction of AM5, AMD has announced it will be moving from PGA to LGA in favor of manufacturing costs and ease of installation.
The socket is also designed to hold the CPU down with the aid of another component, the SAM (socket actuation mechanism)
SAM
The Socket Actuation Mechanism comes in two forms on today’s mainstream motherboards, one for Intel and a separate one for AMD. This is because currently there are two types of socket pin configurations on the market (LGA and PGA).
The socket actuation mechanism is designed to hold a CPU into its socket with some force, this is to ensure good contact between the lands or contact pins on the bottom of the CPU and the motherboard – we call this mounting pressure.
Pressure is applied with the aid of a small leaver to the side of the socket which is clamped after the insertion of the CPU, holding it in place.
Chipset
We mentioned the chipset earlier in the introduction, now it’s time to explain what a chipset actually is.
A chipset resides on every motherboard and is one of the most important components of a motherboard. The chipset is the device that controls the communication between your CPU, RAM, and other components and peripherals. The chipset also determines how many devices such as USB devices your motherboard can support at any one time.
Chipsets are usually composed of one or more chips that feature controllers for not just hardware devices, but more commonly used peripheral devices too, such as keyboards and mice.
If you know anything about motherboards at all we’re sure you’ll be familiar with the terms ‘X670, Z690, B550’, and so on (or at least something of that nature) – these are the motherboard chipsets. The names can seem confusing at first but all you need to know is that they follow a specific hierarchy for both AMD and Intel processors, and the higher the number the better the chipset and the more it will support.
Here is the chipset hierarchy for both AMD and Intel, to give you a better understanding of what chipsets are better.
AMD Chipset hierarchy
Intel Chipset hierarchy
Usually, the better chipsets are lettered towards the end of the alphabet, depending on whether it’s for AMD or Intel. X is better than B for AMD, it’s usually in reverse alphabetical order. So, an X570 chipset will be better than a B450 because the letter is later in the alphabet and the number is higher.
RAM slots
The acronym RAM stands for random access memory, and this is the volatile storage in which the computations and instructions are stored. RAM requires a slot in which to be seated.
Ram slots are slots on the motherboard in which the RAM sits … Pretty self-explanatory. But that’s not all the RAM slots are responsible for delivering power to the RAM as well as transferring data to and from the RAM during normal PC operation.
Some motherboards have more RAM slots than others, some have two and some have four. The reason you do not see any motherboards with an odd number of RAM slots is that RAM operates best in pairs. As the CPU switches which RAM stick it pulls from per cycle.
The CPU also pulls from two specific ram slots before the other, that’s why a lot of motherboards have indication markings displaying which RAM slots you should fill first.
PCI / PCIe slots
Motherboard PCIe slots are where you’d expect to find the average GPU or network card in a PCI slot. PCIe stands for peripheral component interconnect express, with PCI just standing for peripheral component interconnect.
Motherboard PCIe slots, much like RAM slots, have lanes that connect to the CPU. Lanes and PCIe slots improve generationally, with the newest PCIe technology being generation five. Both speed and bandwidth improve with each PCIe generation, allowing GPUs and other peripheral devices to output more data at a greater speed, and have it all processed faster thanks to the faster lane speeds.
There’s a total of 24 PCIe lanes connected to the CPU in modern motherboards, 16 of them are used for the Primary PCIe slot, 4 of the lanes for storage, and 4 for the chipset. However, modern motherboards have the technology to switch PCIe lanes on the fly when they’re not needed, to make sure speed and bandwidth is being added where it’s needed the most.
These slots are often referred to as ‘expansion slots’ and this is from the days of adding Soundblaster cards to older PCs to get an expanded audio experience. These slots do exactly what they say on the tin, and that’s to connect micro-boards that expand your PC’s capabilities.
M.2 slots
NVME M.2 slots are technically PCIe slots as they use the same communication system and PCIe lanes to communicate with the CPU as GPUs do. M.2 storage technology has taken off in recent years with the most advanced version of the storage technology being PCIe Gen 5.
These small slots are located just below the CPU socket in most cases and are capable of transferring data at blisteringly fast speeds. The most recent Gen 5 M.2 SSD features read speeds up to a massive 13000MB/s, with write speeds only slightly lower at 12000MB/s. For context, these speeds are more than double the fastest Gen 4 M.2 SSDs on the market.
To accomplish speeds like this the M.2 slot has to be connected to the CPU directly via PCIe lanes, there are 24 lanes in total and four are dedicated to PCIe storage solutions. The rest are delegated between GPU and chipset.
Motherboard I/O
Motherboard I/O stands for Input-Output, and it’s a pretty simple mechanism allowing your motherboard to connect to and use devices that do not belong to itself. I/O is an all-encompassing term for the connectivity integrated into your motherboard, USB, Audio jack, HDMI, PS2 (if you’re old school), and optical are all motherboard I/O.
The purpose of having all this connectivity is to extend the capabilities of your motherboard, for example, a mouse and keyboard, which are essential to PC usability, are both classed as I/O – specifically peripheral devices.
It’s not just the output section of the motherboard that you can find I/O, it’s actually built into your PC case too. The USB slots on the front of your case are attached to the motherboard, acting as extended I/O.
VRMs
VRMs are incredibly complicated and deserve their own article, but we’ll try to keep things simple for now.
Motherboard VRMs play an integral part in PC operation, and that’s voltage regulation. VRM stands for Voltage Regulation Module and it does pretty much exactly what it says on the tin. The VRM is responsible for delivering consistent, clean power to the CPU at the required voltage. A low-quality VRM can cause a whole host of problems such as shutting down under load and poor overclocking capabilities.
A PSU supplies 12 volts of power to the motherboard. However, sensitive components, like CPUs, can’t handle this level of voltage. That’s where the VRM comes in, by stepping down the incoming 12-volt power supply to 1.1-volts and sending the power where it’s needed.
Most modern motherboards ship with multi-stage VRMs, and these differ slightly from the standard single-stage VRMs. The way multi-stage VRMs work is that when they receive the power they distribute it evenly amongst themselves. The reason this is important is to allow each stage of every VRM to supply a small amount of power individually to the CPU, rather than the full load over single-stage VRMS.
By supplying small amounts of power pre-stage, the VRMs improve heat dissipation among themselves, and can also help power higher TDP CPUs more safely.
Motherboard headers
Motherboard headers are kind of the motherboard’s own internal I/O, ports, and connectors that allow peripheral components to be powered, or allow fancy RGB systems to speak to each other.
Fan headers
Motherboard fan headers are a fairly simple component to wrap your head around, fan headers are headers to which you attach case fans – mind blown.
Fan headers are all 12-volts nowadays and come in a couple of different forms, these are three-pin and four-pin. The three-pin headers are just your standard fan header with little to no control over the speed of the fan. The motherboard may reduce the voltage of the header to control the speed of the fan, but this method has mostly been ousted by the implementation of PWM fans.
The second type of fan header is the four-pin fan header which is capable of fine-tuning fan speeds to suit the PC’s needs. This technology is called PWM (Pulse-width modulation) and controls the fan speed over the header by sending rapid pulses of electricity to the fan. This is why an extra pin is required on the fan header.
USB headers
Motherboard USB headers are not the same type of USB header we discussed in the I/O portion of this article. USB headers are places in which devices are connected that require power and can be controlled by the motherboard.
For example, a decent PWM fan hub requires a connection to the motherboard via a USB header to function properly. The USB header allows data and power transfer rolled into one meat little package. Older fan hubs used SATA connectors, in fact, some still do, but they will have an additional connection over USB. This is because SATA (power) cannot transfer data as it comes from the power supply directly.
RGB headers
RGB headers follow a popular trend along with fan headers, there are two different types. These two types are RGB and ARGB.
RBG headers are three-pin 5-volt headers that allow the RGB device to be powered and display a single color throughout the whole device. This is where ARGB differs from RGB. ARGB stands for addressable RGB, the headers for ARGB components are 12 volts and contain an extra pin, totaling four pins.
ARGB headers and compatible components can display dazzling effects and are able to control the color of each LED individually, as opposed to being confined to one simultaneous color like simple RGB headers.
SATA ports
Motherboard SATA ports are the connection your motherboard makes to SATA storage, these storage solutions include both HDDs and SSDs.
There can be any number of SATA ports on a motherboard, ranging from four ports up to 12 on some high-end boards. The sole purpose of SATA ports is to allow your PC access to the data that’s stored on the SATA storage device. Although M.2 SSDs are quickly making SATA an afterthought in gaming PCDs, it’s still very useful for large-scale data storage, like in server farms.
SATA comes in three forms, SATA I, SATA II, and SATA III. All modern motherboards will (or should) use SATA III as this has a 6GB/s transfer speed, which is twice as fast as SATA II with 3GB/s and four times faster than SATA I (1.5GB/s).
Heatsinks and Thermal Armour
We explained what heatsinks do in another article, but essentially it’s a heatsink’s job to pull heat away from the component it’s attached to and radiate that heat into the atmosphere.
Thermal armor is just another word for a heatsink, only it’s a snazzier more “gamer” way to call a heatsink.
You can usually find thermal armor in three places on most motherboards, on the VRMs as they get very hot when handling high CPU loads, on the chipset as again the chipset can generate a lot of heat under normal conditions, and on at least one of the M.2 SSD slots.
Some chipsets, like the X570, require active cooling. So in addition to thermal armor, you will find a small fan situated above or near the X570 chipset. This is because the X570 chipset is a powerful one and generates a lot of heat. To solve this issue, AMD has split its new X670 chipset into two, to even the heat distribution enough to only require passive cooling.
Motherboard power and CPU power
The astute among you may have noticed that all PCs need power, and by extension so do all motherboards. There are two main power ports on a motherboard, so we’ll divide this section into two parts. But how does a motherboard handle power?
There’s a large number of components with varying voltages on the motherboard to make sure the board gets all the right power, it uses regular pulse-width modulators. For instance, to convert 12 to 1.2 volts the motherboard will close a MOSFET switch for 10% of the time and put it into an LC filter (tank circuit) and this will output 1/10th of the voltage. This applies to all motherboard power, the motherboard will dynamically allocate different voltages where they are needed.
Motherboard power
Motherboard power is handled by one 24-pin power connector, and it usually plugs into the left-hand side of the motherboard. This is where the motherboard gets all of its power from.
Interestingly enough there’s a separate VRM on your motherboard dedicated to handling power to just your RAM, as it’s very volatile. All power supplied to your motherboard comes into the board at 12 volts, and that needs to be stepped down as much as possible. So all power to the motherboard will be converted using a similar method as explained above before the power is directed where it is needed.
Motherboard power handles everything from PCIe power to fan controller power. Everything except CPU power, that’s from a separate source.
CPU power
CPU power is provided via a separate four or eight-pin connector that provides only CPU power to the motherboard. The CPU power connector can be found on the top right of the motherboard just above the CPU socket.
Because the CPU is so sensitive to high voltages, the CPU power socket is surrounded by VRMs to regulate and control the voltage heading for the CPU and the socket. Most CPUs require voltages between 1.1 and 1.3 volts and can’t handle anything much higher, but why does CPU power have to be provided by an additional socket and power system?
The reason is that motherboard power simply isn’t enough alone to power most CPUs, as CPU TDP measures from around 25W to 170W currently with what’s available on the market. Additionally, the power needs to be clean and heavily regulated, so the CPU power socket only accepts 3.3 volts from the power supply as standard.
There are additional CPU and mobo power ports on some high-end motherboards, these ports are to increase the motherboard overclocking potential. With the aim of providing a little extra juice should it be required.
Sound chip
Sound chips are another complicated component, so we’ll only cover the basics here.
All modern motherboard designs include integrated sound chips now, there was a time when motherboards didn’t come with the capability to process audio at all and required an additional sound card – thankfully that’s all in the past, and we can put that fever dream to bed.
Sound comes in two formats, digital and analog. PCs are digital systems, so they can only produce and manipulate digital audio. The issue with this is that audio in the real world is an analog entity, so PCs need a way to process and convert that digital signal into the analog signal that all speakers expect to receive.
This job falls to the audio/sound chip and its subcomponents, specifically the Codec. The Codec is short for encode/decode and is in charge of converting digital signals to analog and vice versa. This component is incredibly important as it defines the audio quality of the sound chip onboard the motherboard.
Sound chips are connected directly to the audio I/O on the back of the motherboard and can convert any signal required on the fly. You can still install a more advanced sound card into your PC, or get a DAC or amplifier if you want better and cleaner audio.
Cmos battery
It’s funny to see all this advanced tech packed into a motherboard and still see a small battery towards the middle bottom of the motherboard, what’s it for?
This component is the CMOS battery. CMOS stands for Complementary metal-oxide-semiconductor, and you’ll get some serious brownie points for knowing that as it’s not common knowledge.
All the CMOS battery does, is power the system clock and the BIOS memory to store all of your BIOS configurations. BIOS memory, like RAM, is volatile and needs to remain powered for it to function properly, as soon as it becomes unpowered it forgets everything it’s ever known.
The standard life cycle of a CMOS battery is three years, so if you’re experiencing problems with storing BIOS configurations after a PC restart, it’s time to change your CMOS battery – you’re welcome.
All motherboard components work collectively to keep your PC running strong.
Final word
That’s about it for this motherboard parts explained article, motherboards are extremely complex and full of smaller even more intricate subsystems that work in perfect synergy to bring your PC to life. Technology is progressing ever forward and with the release of AM5 on the horizon, we can’t wait to see what’s next in the world of motherboards.
