Dmitri guy :
mine is aprox 12" wide by 9.6" deep, so ARX case should be good? thanks for the help
A full size ATX board is 12" wide by 9.6" deep
should i get a mid tower or full size?
As you move from one to the other, the difference is sometimes hard to discern. I forget the actual cut off .... depending on day of week, I blame kids, drink, wimmen or age
....but 21.5: tall might mean mid-tower and 22.5 High is fill tower.
How big would depend on what you need to put in it, how fast you want it to go and how much you wanna spend. I used to keep lists of about 5 cases in multiple size / cost categories, now I'd say 9/10 builds we're involved in go w/ Phanteks...