▷ What is a motherboard and how does it work

Today we have to talk about the motherboard of a computer. The motherboard is undoubtedly the basic element to create a computer, the rest of the components such as the CPU or RAM will be installed on it so that the machine is capable of starting and working. So let's see in detail what a motherboard is and how it works.

Index of contents

What is a baseboard?

The motherboard is without a doubt the most important part of a computer. This is the one that will determine what architecture our team has in its internal components. Each motherboard will be designed to house certain components, or certain types of component families, and will also support certain speeds and capacities that those components have.

All or almost all the components that are part of the computer will be connected to the motherboard, it will also be in charge of establishing a communication bus between those components (CPU, RAM, graphics card) and the peripherals installed on it (mouse, keyboard, screen etc)

Its physical aspect is that of an electronic circuit of certain dimensions in which a series of elements such as chips, capacitors, component connectors and electricity lines are installed, which together form the structure of a computer.

Almost all of them must have four basic components installed:

• Power supplyCentral processorRAM memoryStorage units

The motherboards consist of different physical formats that determine the physical dimensions that these will have.

Motherboard Formats

The formats that we can find in the market come to be the following:

E-ATX

It is the largest form factor we have on the market. Its dimensions are 305 x 330 mm. These boards usually have abundant holes for expansion cards and many possibilities in terms of installing graphics cards in SLI or Crossfire.

In addition, we will have up to 8 slots available for the installation of RAM memory

ATX

These boards have been on the market since 1995 thanks to their implementation by Intel. They are also the most common we can find. Its dimensions are 305 x 244 mm although there are also some with slightly different dimensions. Of course, the holes for its placement in the chassis must be located exactly in the standardized places.

This type of motherboards are used for almost all types of systems, office, gaming, etc. This is due to its wide possibilities of expansion. Normally we have 7 expansion slots and 4 slots for the installation of RAM memories .

Micro ATX

Motherboards with this format have dimensions of 244 x 244 mm, so they are quite smaller than the previous ones, around 25%. These boards, being of a smaller format, are aimed at office work teams, which do not need as many expansion slots and also occupy smaller chassis.

Among its expansion possibilities it has a maximum of 5 expansion slots, although the normal are 3 and spaces of up to 4 RAM memories. This type of plates will need chassis compatible with their fixation since the position of the screws will be different from the ATX plates.

Mini ITX

This is the smallest plate format available for home computers. It has dimensions of 170 x 170 mm. For fixing it consists of four holes that coincide with those installed for an ATX plate.

On these boards we can find a single expansion slot for the graphics card and two slots for RAM memory

There are others formed like the XL-ATX, but they are not usually seen much in the low / mid range. Only in the PREMIUM range

Physical components of a motherboard

This will be by far the widest section in this article, as the motherboard has a host of components worth naming. Let's start then.

Chipset

The chipset or "chipset" is a set of integrated circuits that are designed to establish communication between the processor and the other components installed on the motherboard. These elements can be RAM memory, hard drives, expansion slots, and input and output ports.

With the evolution of motherboard technology, these chips are normally made up of a single central chip. Furthermore, these chips are exclusively designed for a set of processors or a certain brand and for certain RAM memory modules. This makes it necessary that when acquiring a motherboard from the market we are forced to also buy a compatible processor and RAM modules for it.

Old motherboards

The chipset can be integrated by two chips and are also called the North Bridge or North Brigde and the South Bridge or South Bridge. Each of these chips are responsible for certain tasks to be performed:

North Bridge: This chip is directly attached to the processor bus and has direct communication with it and RAM memory. This bus is also called Front Side Bus or (FSB) and is decisive in the speed and performance of a computer. In addition to this, it is also in charge of communication with the PCI-Express ports, since these are the ones that support the fastest components such as the motherboard or the new M.2 and PCI-E solid state storage units.

South Bridge: This chip is directly connected to the north bridge through the Direct Media Interface or (DMI) bus. This chip is in charge of the communications of the input and output devices and of connecting these with the north bridge. For example, SATA hard drives, USB, Fire Wire, network card, AUDIO, etc.

Modern motherboards

Currently with the appearance of multi-core processors such as Intel Core and AMD FX this chipset has been significantly reduced to a single chip, thus disappearing the south bridge.

This is because the new processors integrate the memory controller within them, so they are directly connected to the RAM memory bus. Let's say that the FSB bridge is integrated within the processor and the bus in charge of the other devices is called the Plataform Controller Hub (PCH), replacing the DMI bus.

Chipset types

There are a large number of chipset models. With each evolution of the processors there is also an evolution of these chips. As in everything, there are low-end, for a lower or lower speed component management, a mid-range and a high-end that offers maximum speed and support for various graphics cards and the fastest RAM on the market.

According to the processor manufacturer, we can find chipsets designed for AMD processors, and chipsets designed for Intel processors.

For more information on the latest marking chipset models for both technologies and their comparison, visit our following articles:

Microprocessor Socket

As it could not be otherwise, on the motherboard is where the microprocessor must be installed and for this a socket with the physical connectors will be necessary to communicate this with the motherboard. There are two types of sockets:

• PGA (Pid Grid Array): in this socket there is a panel with holes to insert the microprocessor inside, which will have contact pins for insertion. LGA (Land Grid Array): The socket features a matrix of gold-plated contacts that make contact between the motherboard and the processor chip, which only has a flat surface with contact points.

The insertion technology is called ZIF (Zero Insertion Force) and the chip does not fit perfectly in the socket if you need to apply force in the process.

As with processors, there are many types of sockets for your installation. This means that when buying a motherboard of a certain architecture, it is necessary to acquire a processor compatible with it.

In addition, each motherboard is designed for a processor manufacturer, so both the socket and the chipset must be compatible with the brand in question.

To learn more about how a processor works, we recommend the following article:

• What is a processor and how does it work?

RAM memory slots

These connectors or buses are in charge of housing the RAM memory modules that will be installed in the equipment. In general, motherboards have 4 slots or high-end motherboards have 8.

These slots will usually be designed to work with dual channel technology or even quad channel technology. As with the processor, each motherboard will support a certain architecture of RAM.

The motherboards currently have different types of RAM slots, although they all belong to the DDR standard. We will have: DDR, DDR2, DDR3, and DDR4

To learn more about how RAM works, we recommend our article:

• What is RAM and how does it work?

VRM

Acronym for Voltage Regulator Module. They are a set of components that transform the electric current that reaches the motherboard to voltages of different values ​​and intensities so that they are used by the other components installed on it. This component, despite not being particularly eye-catching, is essential for the components to function correctly and to avoid breakage.

To know more about these components visit our article:

Expansion slots

They will be the slots that have the functionality of expanding the hardware installed in our equipment. In them you can install graphics cards, hard drives, network cards, sound cards, etc.

These slots are currently called PCI-Express or PCI-E and are substitutes for traditional PCI. Each PCI-E expansion slot carries 1, 2, 4, 8, 16, or 32 data links between the motherboard and the connected cards. We encode this number of links as a prefix x, for example, x1 for a single or unit link and x16 for a card with 16 links, which are used for graphics cards. Each of these links gives a speed of 250 MB / s.

If we have 32 links, they will give the maximum bandwidth, that is, 8 GB / s in each direction for PCIE 1.1. The most commonly used is the PCI-E x16 which provides a bandwidth of 4GB / s (250MB / sx 16) in each direction. A single link is approximately twice as fast as a normal PCI link. 8 links have a bandwidth comparable to the fastest version of the AGP bus, which are the old slots for graphics cards.

BIOS

The BIOS or Basic Input-Output System is a ROM, EPROM or Flash-RAM memory that contains information about the configuration of the motherboard at the lowest level.

Inside the BIOS there is also a memory chip called CMOS, with the program it stores inside, it is able to initialize all the physical components of the board in order to start the computer. In addition, it is responsible for checking them for errors or absence of devices, for example, lack of RAM, CPU or Hard Drive.

The BIOS memory is continuously powered by a battery. In this way, when the machine is turned off, the data and parameters configured in the computer are not lost. If in any case this battery is exhausted or we remove it, the BIOS information is reset to the default values, but they are never lost.

Sound card and network card

They are the chips in charge of processing the multimedia sound of our equipment and the network connection. Its chips are located near the output ports of the motherboard and we can identify it on many occasions by its RealTek distinctive since it is the manufacturer of many of these devices integrated on the motherboard.

SATA connectors

This is the communication standard in today's PCs for connecting mechanical hard drives and also SSDs. In SATA, a serial bus is used instead of parallel to transmit the data. It is much faster than the traditional IDE and more efficient. In addition, it allows hot connections of the devices and has much smaller and more manageable buses.

On a motherboard we can have up to 6 or 10 of these ports to install hard drives. The current standard is found in SATA 3 that allows transfers of up to 600 MB / s

To learn more about how a hard drive works, we recommend the following article:

• What is a hard drive and how does it work?

M.2 connector

Almost all the boards already have this port installed. M.2 is the new communication standard intended to replace the connection for SATA SSD drives in the medium and short term. It uses both SATA and NVMe communication protocols. M.2 is exclusively intended for the installation of storage units in this way we avoid occupying PCI-E slots. This standard does not have the speed of PCI-E but is much higher than SATA.

To learn more about how an SSD works, we recommend the following article:

• What is an SSD and how does it work?

Power connectors

The motherboard must connect to a power source and for this it has different types of power connectors.

ATX

It is the traditional connector that powers the motherboard in most of its components. It is made up of 24 cables or pins and is normally located on the right side of it, next to the RAM slots.

CPU power

In addition to the ATX2 connector, almost all new motherboards, at least the ATX, also have this type of connector intended exclusively to power the processor. These types of power supplies help to increase the power supply of the motherboard, especially in cases of overclocked processors that need more power for consumption.

We can find a 4-pin CPU connector (older), one of 8, or one of 4 + 6 pins. Its functions will be practically the same, and all of it goes with a 12V voltage.

External connectors

These connectors will be located on one side of the motherboard, almost always on the left. You will be in charge of connecting the peripherals that we have in our setup, for example, printers, mice, keyboards, speakers, storage units, etc. We can distinguish the following types:

• PS / 2: There are two ports of this type, already practically in disuse. They have 6 pins and are intended to connect the keyboard and the mouse. Virtually no keyboard has this type of connector, so they are moved and replaced by USB USB (Universal Serial Bus): it is the most widely used serial connection standard worldwide. This connector is plug and play, so we can connect a hot device so that the operating system recognizes it immediately. In addition to data exchange, it also enables peripheral alignment, making it very convenient and versatile. There are currently four versions of this port, USB 1.1 with a speed of 12 Mb / s, USB 2.0 with 480 Mb / s, USB 3.0 with 4.8 Gb / s and USB 3.1 with 10 Gb / s FireWire: It is a standard similar to USB, but mainly used in America. They have practically the same functionalities as USB and it has 4 versions, the fastest being the FireWire s3200 with 3.2 Gb / s HDMI or DisplayPort: These ports will exist if the motherboard has an integrated graphics card. It is a digital multimedia communication standard that allows connecting high definition video devices. Both video and audio signals travel through these ports, making them especially useful. Currently they have practically completely replaced the VGA DVI and VGA port : ports to connect the HDMI predecessor Ethernet screen : port intended for the RJ 45 connector on the internet 3.5 "Jack: Connector for audio input or output devices

Other elements

• Internal ports for USB: connectors are available at the bottom of the motherboard to expand the USB ports of our equipment. The available USB ports on the chassis will normally be connected. Internal sound ports: As with USB, the board has an internal port to connect microphone and speakers from ports arranged in the chassis. Clocks: to synchronize all the internal components, a series of clocks that work at different frequencies is necessary, depending on the needs of each component. Fan connectors : These are 12V connectors intended to insert fans such as the CPU or chassis fans. They have 4 pins. Starter panel: they are a series of power connectors where the buttons on the chassis are connected, which are responsible for starting and resetting the system. The hard drive and power LEDs will also be connected.

Operating a motherboard

The operation of a motherboard is quite complex, due to the large number of elements installed on it and the number of buses intended for the exchange of information. Schematically we can represent it in the following way:

In this scheme, we can distinguish the main elements that intervene in the operation and management, and take the starting process of a computer as a reference:

The first thing a motherboard should do before loading the operating system from the hard drive is to initialize the components. The program located in the BIOS is in charge of checking all the devices connected to it: CPU, RAM and Hard Disks in a basic way. If any of them is missing, broken or detects other anomalies, the motherboard will emit an error code translated in sound beeps or also by means of a code in an LED panel located on it.

Once the verification stage is completed, the internal bus is loaded with information from the storage units. Here the southern bridge (if it exists) and the northern bridge intervene.

After requesting the information from hard drives, and input / output devices and other components, the north bridge is responsible for connecting the processor with RAM. This is done through the front bus or Front Side Bus (FSB). This will consist of 64 threads or 64 + 64 in case of implementing dual channel technology.

In any case, the operating system data loaded in memory will already be found to boot the computer.

Simultaneously, the north bridge will send the graphics signals to the graphics card, installed in a CPI-E x16 slot directly managed by it. Or in your case, it will connect with the graphics card installed on the motherboard itself. This is done by the FSB bus.

In any case, the computer will start and the data exchange for processing will be managed by the elements connected to the bus and the chipset.

Final conclusion and expectations about what is a motherboard

If one thing has become clear to us is that it is increasingly difficult to explain the operation of the components of a computer in a simplified way. Technology is advancing at an incredible rate and the elements are becoming more complex and more functional and complex.

At the rate that we are going, it is possible that the 5 nm barrier will be reached in a very short time and we will see to see that the great companies devise to go further.

For our part, we are delighted with these advances, increasingly faster, more complex equipment and at a sustained price if we go to mid-range components that are also very good.

We also recommend our article on quantum processors

• What is a quantum processor and how does it work?

We hope that with this article you have learned more about the components of a motherboard and its basic operation. For any doubt, clarification or error, do not hesitate to tell us.