I personally have a ATX case back in the 90's to millennium, and the graphic card is thin and not too big. Quite spacious when putting into.
But now I am building a new fast computer, with mATX case. I realize if i put a new radeon card in, there is not much space left and not even i want to try cross-fire to maximum the power.
Does anyone also feel the same? I hope to more small card but bigger power.