Home News&Events Blog The Complete Guide to Motherboard Form Factor Varieties

    The Complete Guide to Motherboard Form Factor Varieties

    motherboard form factors sizes

    What is form factor?  

    Each component is specifically designed to fit a certain size and design specifications in the hardware world. This is especially true in computers, where internal hardware like motherboards, storage drives, and memory modules vary widely in shape and size. This variation is referred to as the 'form factor.' Essentially, the form factor is a term for the design blueprint of hardware components, dictating their shape, size, and other physical characteristics, ensuring that they fit and function seamlessly in a computer system.

    What is Motherboard?

    The motherboard is a computer's backbone, serving as the primary platform where key components like the CPU, RAM, and expansion cards are connected. It facilitates communication and power distribution among these components and includes ports for external peripherals and storage devices.

    Different types and sizes of motherboards

    Motherboards come in various types and sizes, catering to different needs and specifications of computer systems. The most common types are:


    The standard ATX (Advanced Technology Extended) is the most widely recognized and used motherboard form factor. Developed by Intel in 1995 as an evolution from the older AT/Baby AT designs, ATX motherboards measure approximately 9.6 by 12 inches. Predominantly found in desktop computers globally, their popularity stems from their efficient performance and versatility. ATX boards provide ample space for numerous I/O ports, PCIe lanes, and SATA connections, catering well to enthusiasts and various computing needs. Additionally, they introduced sleep mode in power management, enabling systems to enter a low-power state and resume seamlessly. Since 2017, ATX has become the default standard in many PC builds.


    • Offers extensive expansion options with multiple slots for hardware upgrades.
    • Widely compatible with various cases and power supplies.
    • The larger size allows for more efficient cooling solutions.
    • These motherboards are feature-rich, including numerous USB and SATA ports.
    • The larger size makes ATX unsuitable for compact PC builds.
    • ATX boards generally have higher power consumption.
    • ATX forms tend to be more expensive due to their size and features.
    • ATX can be excessive for basic computing needs, offering more than required.

    Micro ATX  

    The Micro ATX, a compact version of the standard ATX motherboard, offers a smaller form factor while maintaining backward compatibility with ATX-sized cases. It supports many of the same components as the standard ATX but differs mainly in having fewer expansion slots (up to 4 compared to ATX's 7). This makes the Micro ATX a favored option for those prioritizing cost-effectiveness and space efficiency over extensive expandability.


    • Design compact and space-efficient, suitable for smaller PC builds.
    • Generally more affordable than larger motherboard options.
    • Offer adequate expansion capabilities for most users.
    • Compatible with ATX cases, allowing for versatile case choices.


    • Limited expansion slots compared to ATX, restricting high-end upgrades.
    • Their smaller size can lead to a cramped layout, complicating installation and cooling.
    • Often have fewer features and ports than ATX motherboards.
    • Less suitable for extreme performance tasks like overclocking or multiple GPUs.motherboard size comparison

    (Image source: Wikipedia)

    Small Form Factor Motherboards 

    Stepping beyond the ATX series, we encounter the ITX (Information Technology Extended) motherboards, developed by VIA Technologies in 2001 specifically for small form factor PCs. Designed to fit in compact spaces, ITX boards significantly reduce the number of component slots to achieve their small size. These motherboards, which come in various sizes, are particularly tailored for embedded systems and space-constrained configurations.


    The Mini-ITX, the pioneer among various ITX sizes, was specifically designed for compact applications, such as in-vehicle computers and industrial automation, commonly found in the embedded space. Its popularity stems from its suitability for physically constrained spaces, low power consumption, and the ability to utilize passive cooling through heatsinks.

    • Highly compact, ideal for small form factor and portable PC builds.
    • Low power consumption makes it energy-efficient and less heat-generating.


    • Limited expansion options due to fewer slots and connectors.
    • Often more expensive per feature compared to larger motherboards.

    Nano-ITX, Pico-ITX, 3.5” Industrial Motherboard, & FEMTO-ITX 

    Following the Mini-ITX, a range of even smaller ITX motherboards emerged, ranking among the smallest motherboard sizes available. These boards are typically fully integrated, with key components like the CPU and controller cards built directly onto the motherboard, as opposed to using expansion slots or separate installable components. Single-board computers exemplify this integrated design, selling essential components onto the board and providing a reliable and power-efficient solution.


    Introduced in 2003 by VIA Technologies, the Nano ITX was the first in the series of smaller ITX boards. Measuring 12cm x 12cm (about 4.7 inches), these motherboards are fully integrated and known for their low power consumption. Their compact size makes them ideal for smart entertainment systems and in-vehicle devices.

    • Ultra-small size, ideal for extremely compact and portable computing solutions.
    • Efficient power usage, suitable for low-power applications and minimizing heat generation.


    • Very limited expansion options due to their small size.
    • Typically higher cost and less feature-rich compared to larger motherboard formats.

    3.5” Industrial Motherboard 

    3.5 inch industrial motherboard single board computer

    Deviation from standard form factors begins with the 3.5” industrial motherboard, designed to match the size of a 3.5” hard disk drive. Despite its small size, it boasts a rich array of I/O capabilities, suitable for various industrial uses. Interestingly, the "3.5” is not the size of this motherboard; the real size measures 5.75” x 4”. 


    • Compact and space-efficient, it fits easily into small industrial devices and applications.
    • Durable design tailored for harsh industrial environments, withstanding extreme conditions.


    • Limited expansion capabilities due to its small size and industrial focus.
    • Potentially higher cost, given its specialized design for industrial applications.


    The Pico ITX, another creation of VIA Technologies, is the smallest in their ITX series, measuring just 3.9in x 2.8in, half the size of the Nano ITX. Designed to foster innovation in compact and intelligent IoT devices, the Pico ITX combines minimal size with efficient performance, operating on a low TDP (Thermal Design Power) under 10 watts. This design enables the integration of x86 or 32-bit CPU performance into embedded systems at a remarkably low power consumption.


    • Extremely small size, perfect for ultra-compact and portable applications.
    • Low power consumption, ideal for energy-efficient and low-heat generating systems.


    • Very limited expansion capabilities due to minimal space for additional components.
    • Higher cost per feature, as miniaturization often comes at a premium price.


    femto Itx 1.8 inch industrial motherboard

    The FEMTO-ITX is the latest and smallest form factor discussed in this article, roughly the size of a credit card, making it ideal for extremely space-limited applications. Similar to the Pico-ITX, the FEMTO-ITX paves the way for more innovation in compact, rugged-edge designs. While comparable in size and functionality to the popular DIY Raspberry Pi, the FEMTO-ITX is more tailored towards industrial uses, offering greater versatility in its I/O capabilities.


    • Exceptionally small and compact, ideal for the smallest possible computing solutions.
    • Highly energy-efficient, with minimal power requirements and heat generation.


    • Extremely limited in terms of expansion and connectivity due to their tiny size.
    • Potentially higher cost for specialized, ultra-compact design and technology.


     Form Factor Dimensions Applications PCIe Slots

    Standard ATX

    12 × 9.6 in

    Desktop PC  2-3x PCIe x16 
    2-3x PCIe x1 
    Micro-ATX 9.6 × 9.6 in Small Form Factor 

    1-2x PCIe x16 
    1x PCIe x4
    1-2x PCIe x1 

    Mini-ITX 6.7 × 6.7 in  Small Form Factor

    1x PCIe x16
    1x Mini PCIe

    Nano-ITX 4.7 × 4.7 in  Embedded System

    1x PCIe x16
    1x Mini-PCIe 

    Pico-ITX 3.9 × 2.8 in  Embedded System 2x Half-sized mini PCIe 
    3.5" Motherboard 5.7 x 4 in  Embedded System 1x Mini PCIe 
    FEMTO-ITX 3.3 x 2.1 in  Embedded System 1x Mini PCIe 

    What are Industrial Motherboards and How are they Different?   

    industrial motherboards single board computer integrated motherboard


    In rugged and industrial settings, standard components like ATX motherboards often don't fit due to limited space and harsh conditions like extreme temperatures, shocks, and dust. This necessitates systems that are low in power consumption yet capable of adequate performance. Applications such as industrial automation, vehicle systems, digital signage, medical imaging, and security rely heavily on small form factor motherboards. These motherboards, including 3.5" versions with a Single Board Computer (SBC) design, integrate all components on a single substrate and are ideal for low-power, entry-level industrial tasks.

    Key advantages of small form factor motherboards in industrial settings include:

    • Size: Their compact dimensions are crucial in space-constrained industrial environments, allowing necessary performance in limited spaces.
    • Power Efficiency: These motherboards and PCs generate less heat due to lower processing power, extending lifespan, reducing cooling costs, and often utilizing passive cooling.
    • Longevity: Designed for durability, industrial motherboards have a long lifespan with minimal need for maintenance or replacement, reducing total ownership costs.
    • Durability: Built to endure tough industrial conditions, they resist dust, debris, water, shock, and vibration. 

    C&T’s Line of Industrial PCs, Motherboards, and SBCs 

    premio family product industrial pc and industrial motherboard

    C&T offers a diverse line of single-board computers and industrial PCs, encompassing standard small form factors and custom-designed motherboards for specific product needs. These devices are engineered to excel in rugged environments, making them ideal for industrial applications that require robust and reliable computing solutions. The product range includes fanless embedded computers and a variety of edge computing devices like mini IoT gateways and industrial-grade computers, all built to withstand wide temperature ranges, voltage variations, and significant shocks and vibrations.

    Learn more about our Industrial and Rugged Edge Computers.


    C&T's industrial motherboards are central to embedded computing, offering reliable, durable, off-the-shelf solutions for challenging applications. They also provide comprehensive services for design challenges, from custom solutions to minor I/O modifications. Each motherboard is adaptable to meet specific requirements without sacrificing performance. Recently, Premio has integrated AMD Ryzen Embedded SoCs into their 3.5” and 1.8” FEMTO-ITX single-board computers, adding an option for x86 performance and I/O flexibility in a compact form factor.

    Learn more about our Industrial Motherboard 


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