I'm not sure weather or not to put this in Motherboards or Audio..... The issue im having is that when ever I plug something into the rear io audio connector there is aconstant noise in the heaphones. It is really annoying. I know that onboard audio isn't very good but I dont have money for a sound card right now. This seems like something that shouldn't happen even on onboard audio.
Actually the Crosshair V Formula-Z boasts a beefy sound card for being built in. Do you have the audio ports for the from of the case hooked up? if so is that different? What headphones are you using?