The extreme 4 is an ATX board (essentially the normal sized board) while the mobo in your build is an mATX board (mini) which typically have fewer features in order to reduce the size. The only real reason to get a mATX board is if you have a mATX case. Also, Asrock has been making pretty good quality motherboards for a bit cheaper than their competition the past few years (probably in an attempt to improve brand recognition, they were formerly a subsidiary of ASUS).