TechRadar outlines the differences between different motherboard sizes and their different features and functionality ...
only the keyboard connector was attached to the motherboard. Numerous variations of the ATX were subsequently introduced with both smaller and larger form factors, including the microATX, Mini ATX ...
and Mini ITX. Intel pioneered the ATX and Micro ATX motherboard and power supply formats. However, companies like IBM, SSI, VIA, and AMD created many standardized motherboard form factors.