Thanks for the reply.   Yes, I did that before installing the card and have since tried to re-enable it but it makes no difference.

I picked up the Asus DGX a couple of weeks ago and this has been an issue from day one.   When I change the Analog Out to 'Headphone' this low hissing sound starts immediately but the same problem does not occur if they're set to '2 speakers'. http://i.imgur.com/93m0gSn.png?1   I can sit...