Question: what is matx form factor?
Answer: microATX (sometimes referred to as μATX, uATX or mATX) is a standard for motherboards that was introduced in December 1997. The maximum size of a microATX motherboard is 9.6 × 9.6 in (244 × 244 mm). The standard ATX size is 25% longer, at 12 × 9.6 in (305 × 244 mm).