The Extreme is an E-ATX board it is a little wider than the Hero or Hero Alpha, the Extreme has all the bells and whistles plus it may have better power delivery system and some overclocking friendly features, pcie lane switches, OC Panel, voltage read points, where the Alpha is a standard ATX board with most the features of the Extreme, still excellent overclocking features and RGB headers, there may be some cases that the Extreme may not fit in which you should check if you already have a specific case picked out. Both are top of the line feature packed beautiful motherboards
