When using AMD Hi Def audio through my HDMI to my Onkyo Windows reverts to 2 channel stereo. This is driving me nuts. It happens if I change the sound mode on the AMP, for example switching from 4 channel stereo to Dolby Digital. When I do that the subwoofer stops working and when I go into control panel>sound and right click and select 'configure speakers' it will show 2 channel stereo and I have to go back in and setup my 5.1 speakers, AAAARRGGG! It even seems to do this if I exit GTA V or if I minimize a game and play a song on ITunes.