not really, both serve the same function. you may buy an additional sound card and use both or disable one. if you are particular about the audio processor, this mb i beleive has a regular 192khz/24bit Azalia processor, with 8 channels, jack sensing and multi streaming features. if you buy a sound card be sure you buy something better (creative, auzen, turtle beach etc.) infact asus xonar is recieving high acclaim, and that could be a good hardware marraige for you asus mb.
gluck
k