Bhaskie - I saw one of my quoted messages there with the text saying that I am using Xonar with Vista. I am sorry, that is wrong. I must have been dreaming when I wrote that. Vista is the stuff of bad dreams actually
I use only Windows XP.
About trying out the mobo's output, no I have not tried that. But I have tried connecting the sound card to the receiver using digital out (coaxial). And I get a far better sound when I use the analogue outs.
I have not tried a headphone at all. I am not a headphone guy, I am afraid.
About noise - no, I dont get any noise regardless of whether I use analogue or digital outs. Also when you say noise, what do you mean? A sibilant hiss when nothing is playing?
About bit perfect audio, yes the Xonar will do that. When you are in 7.1 Channel audio, if you look at your AVR's display it should be able to tell you that you are listening to audio in PCM 96/24 if you are upsampling audio to 96 khz and keeping your audio at 24 bit.