Types of Motherboards: Types and Form Factors Explained in 2022

If you are a beginner who wants to build a computer for yourself for the first time, you should at least have a hint of the fundamental components for building a computer. The motherboard is one of the core components without which a computer can’t be built. If you want to know more about building a PC, you should check our step-by-step guide on building a PC.

Now if we want to describe the motherboard form factor in one sentence, we would say – anyone can get an idea of the size and shape of a motherboard through its form factor. Judging by your PC case, mounting holes, power supply, and physical layout; you should choose the right motherboard form factor. And that brings us to know about the types of motherboards depending on the form factor.

In this article, we will tell you everything you possibly need to know about motherboard types, their functionalities, and their differences.

Table of Content –

First, You Need to Know About Motherboard Form Factor

Back in 1983, IBM initiated a plan to build a personal computer for themselves. Hence, that promoted the creation of a motherboard form factor. That motherboard had an XT form factor. Manufacturers like ASUS, Intel, ASRock, Gigabyte, and more used it as their standard to manufacture their signature motherboards, which can be called “de facto standard” in other words.

The motherboard is a component of a computer that maintains a relationship between all other components. All the elements of a computer such as CPU, RAM, storage disk, graphics card, I/O connectors are attached to a motherboard and they interact with each other through it. Therefore, you should have adequate knowledge of motherboard sizes and all the types of motherboards. Start by knowing motherboard form factors and you will understand everything sooner or later. You can also read our article for choosing the right motherboard for your PC.

All Types of Motherboard Form Factors and Their Functions

How many types of motherboards are there? What are the sizes of motherboards? Now, we will answer all these questions. Advanced Technology Extended (ATX) is the revolutionary evolution of the Baby AT form factor. With many improvements like integrated I/O ports, less interface, better airflow; the ATX is the most widely used form factor today. However, some other form factors like Micro ATX, Extended ATX, Mini ITX were released over the years, based on this form factor. Let’s take a look at the commonly used motherboard form factors –

Motherboard Form Factors

  • Extended ATX (EATX) Motherboard:

    These are slightly longer variants of the standard ATX motherboards. These motherboards can only be fitted inside casings that are labeled for EATX. Usually, the PC cases that are built for ATX motherboards, support EATX form factors as well. With a dimension of 12 x 13 inches, these motherboards provide ample space to keep other components cool. Although EATX motherboards can be used for common desktop works, they are mainly used in workstations and servers. These types of motherboards are designed to support multiple GPUs and hold up to 8 RAM slots sometimes.

  • Standard ATX Motherboard:

    Perhaps, this is the most common form factor that can be fitted in PC cases that are compatible with either ATX or EATX motherboards. Although the dimensions of such motherboards are usually (12 x 9 inches), this can be slightly changed based on the manufacturer. These types of motherboards offer enough space between components for better airflow and can be used for heavy workloads.

  • Micro ATX Motherboard:

    This type of motherboard is the smaller evolution of the ATX form factor. With a measurement of 9.6 x 9.6 inches, these motherboards can be placed in more compact cases. Although the positions of mounting holes are different from a standard ATX because of the change in measurements, these form factors can be easily set up into regular ATX cases. And combining with the PCI, ISA, AGP slots; these motherboards can support up to 4 expansion slots. These types of form factors are available for both Intel and AMD processors.

  • Mini ITX Motherboard:

    The dimension of the Mini ITX motherboard is a matter of discussion since it’s only 6.7 x 6.7 inches. This type of motherboard was designed with the aim of low power consumption. However, the application of usage has been expanding due to the benefits that are rare in other form factors. For industrial applications, vehicle embedded systems, IoT, and other relevant applications; the Mini ITX form factor is becoming a standard format.

  • Nano ITX Motherboard:

    Motherboards having Nano ITX form factors can be seen on smart entertainment devices like smart TVs, PVRs, media centers, in-vehicle computers, and more. These peculiar types of motherboards measure 4.7 x 4.7 inches. Being small, these form factors are effective for low power consumption. These types of motherboards have not yet become very popular for desktop computers. However, we assume it will not be too late for this to happen with the advancement of growing technology.

  • Pico ITX Motherboard:

    Can you imagine this is 75% smaller than the Mini ITX form factor? Thus, it makes this form factor the smallest type in the whole motherboard system. The measurements of the Pico ITX form factor are 3.9 x 2.8 inches. Pico ITX motherboards run on x86-based platforms and developed by VIA so that they can innovate tiny and smart IoT devices. Like Mini ITX motherboards, these also consume low power thus making them an excellent choice for developing embedded system applications.

A Brief Comparison Table of All Types of Motherboards

Now that we have discussed all the motherboard forms factors, we will present a comparison table so that you can get an overall idea at a glance –

Form Factor

Dimensions (width x depth)


Origination Date

Expansion Slots


Extended ATX (EATX)

12” x 13”

Supermicro / Asus


Workstation/Desktop/ Server


12” x 9.6”





Micro ATX

9.6” x 9.6”





Mini ITX

6.7” x 6.7”




Automobiles/ Set-top boxes/ Network devices

Nano ITX

4.7” x 4.7”




Embedded Systems

Pico ITX

3.9” x 2.8”




Embedded Systems

Second, You Need to Know About the Components of a Motherboard

Once, you have gained some knowledge on the motherboard form factor, now it’s time to know about its components. We can consider all the components of a motherboard are the sub-elements of BIOS, CPU Socket, PCI Express, SATA Connectors, IDE Connectors, Power Connectors, Expansion Slots, AGP Slot, Memory Slots, and CMOS Battery. Now let’s break it down for you one-by-one.

Components of a motherboard

BIOS (Basic Input Output System)

BIOS is an integrated chip on a motherboard that allows you to modify the basic configurations. The BIOS contains all the information and lets you control that information by displaying a user-friendly interface on the monitor.

CPU Socket

We can consider it as the main component of a motherboard. This is where the CPU or processor is being placed. Depending on the processor type, there can be various types of CPU sockets. You should be aware that not all processors are compatible with all CPU sockets. Here are the main types of CPU sockets –

  • Socket 7: Some older processors like AMD k5/k6, Pentium 1/2/MMX, Cyrix M2 are compatible with this type of socket and it includes 321 pins.
  • Socket 370: The Pentium 3 and Celeron processors are supported with this socket and the socket usually contains 370 pins.
  • Socket 775: This type of socket supports Intel dual core. Xeon, C2D, P-4 processors. This socket contains 775 pins.
  • Socket 1156: A socket that supports relatively new processors like Intel i3, i5, i7 processors and it comes with 1156 pins.
  • Socket 1366: All the latest and high-end processors like the Intel i7 9900k processor are compatible with this type of socket. This socket has 1366 pins.

PCI Express

These can be found on the latest types of motherboards, supporting additional cards (VGA cards), and full-duplex serial bus. These are also known as PCIe.

SATA Connectors

“Serial Advanced Technology Attachments” is the full form of SATA, which are the 7-pin connectors used to connect the storage drives like HDD, SSD, or optical drive to the dedicated host bus adaptors. These connectors are faster compared to the IDE connectors.

IDE Connectors

To interact with disk drives, Integrated Drive Electronics or IDE connectors are used. There are 2 variants of IDE connectors. One with the 40-pin male connector usually connects IDE hard disk drives and another 34-pin male connector is for connecting Floppy disk drives.

Power Connectors

In order to operate, the motherboard needs power from the SMPS (Switched Mode Power Supply). Therefore, power connectors are integrated into a motherboard to get power. Based on generation, there can be seen two types of power connectors, which are –

  • ATX connector – These are either 20 or 24 pin female connectors, found in all the current-gen motherboards.
  • AT connector – These are either 2 or 6 pin male connectors that can rather be found on the previous-gen motherboards.

Expansion Slots

In order to expand the functionality of your motherboard, these types of slots are needed. As the name suggests, these types of slots can be used to expand the functionality by inserting an additional sound card, network card, WiFi, and VRAM. Two types of expansion slots can be found on a motherboard based on the generation.

  • PCI Slots:
    These are the widely used slots that are currently being used in all the latest motherboards for installing add-on cards. Peripheral Component Interconnect (PCI) are high-speed slots that support 64-bit bus speed.
  • ISA Slots:
    Industry Standard Architecture or ISA slots were found in the oldest motherboards that usually had AT form factors. These types of slots can no longer be seen. Supporting 16-bit bus speed, these slots used to connect sound cards or conventional display cards.

AGP Slot

These types of slots are used in the current-gen motherboards to connect the latest high-end graphics cards. Accelerated Graphics Port (AGP) can run on a 32-bit bus system. To install a sophisticated graphics card, either PCI or AGP or both may need to be used.

Memory Slots

Memory slots are used to install RAM on the motherboard. SIMM and DIMM are the two types of RAM slots.

  • SIMM Slot:
    Single Inline Memory Module (SIMM) slots were found in previous-gen motherboards for inserting RAM and supported a 32-bit bus.
  • DIMM Slot:
    Double Inline Memory Module (DIMM) slots are used in the latest motherboards for installing RAM and support up to a 64-bit bus.

CMOS Battery

The Complementary Metal Oxide Semiconductor (CMOS) is a 3.0 volts lithium-ion button cell and it is in charge of storing the information in BIOS. Typically, the CMOS batteries found on our motherboards are known as CR2032.

Final Words…

The form factor is the crucial element for building any device whether it is a large size industrial IoT device or a tiny smartwatch. The size of the device entirely depends on the size of the form factor. If you have read this article, you may already understand that ATX is the most common form factor among all. In order to fill the necessity, other form factors like mini ATX, nano ATX, pico ATX were invented, which are basically the evolution of the ATX form factor. Thanks for reading this article, we hope you have enjoyed it.

Hi! I am Tanzil, I would like to think of myself as a Tech Nerd. The interest in computers, related parts, accessories, and new technologies have been growing constantly in me. Eventually, the interest became a passion and the passion became a habit. I like to express this habitual knowledge through writing. Therefore, I spend my leisure time writing on computers and technology.

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