As can be evidenced from the motherboard size chart above, there's quite a dramatic difference in scale between Mini-ITX and MicroATX, with more of a subtle difference when comparing ATX and EATX ...

Confused between EATX and ATX motherboards? Learn the key differences in size, features, and compatibility to choose the ...

The most mainstream and common motherboard form factor, ATX was created by Intel in 1995. The typical size of an ATX motherboard is about 9.6" x 12". EATX: 13" x 12" -- A fully-featured ATX ...

(Advanced Technology EXtended motherboard) The PC motherboard that superseded the Baby AT design. The ATX layout rotated the CPU and memory 90 degrees, allowing full-length expansions to be ...