i just want d board for gaming and maybe oc ,will Maximus IV Gene-Z be a better choice than pro
and what is micro atx board
Depends On You.
Primarily it refers to the size of a motherboard. It's actually about 80% (or so) the size of an ATX board. It should (the mobo) mount on the same bolt pattern as an ATX board, however, it won't cover all the holes.
When other products, (heat sinks, cases, power supplies and such), are mentioned in conjunction with Matx, it's generally to imply compatibility.
Intel lists Matx (motherboards) as about 9.60" x 9.60".
The ATX specs are 11.60" x 9.60".
With respect to cases a Matx only case would likely be called a "mini-tower".
Almost all "mid-tower" cases would accept both spec boards.