Audio Bitstreaming

I am about to convert from the world of desktop/headphone (head-fi) computing to home theater (HTPC) computing. (darn ringing ears cant take the headphone goodness anymore...)

My understanding is that currently only a few graphics cards support full audio bitstreaming. The top of the line is currently the GTX 460 right? (hopefully the GTX 560 continues with this).

Currently I use a USB to S/PDIF transport for 2 channel audio. My onboard sound is disabled and I have no sound card.

If I buy a GTX 460 or 560, will I simply be able to plug in the HDMI from the GPU to my A/V Receiver and be done with it? I found an article on the web that said I must turn on my onboard audio too....hopefully this is not true.

What other cards support bitstreaming?

My understanding is that the 4XX and 5XX series cards from nvidia support native HDMI out. You shouldn't need to enable on-board audio.

Nvidia's older cards with HDMI-out (ie 2XX series) actually used a spdif pass-through from a separate source, so you had to run a cable from the on-board or add-in audio card to the video card.

By "bitstreaming" do you just mean digital audio over HDMI or do you want to stream the ultra high quality audio off blurays? You might get a better response to this questions in the Home Theater section of this forum.

http://hardforum.com/forumdisplay.php?f=103

To add a little, bitstreaming on nvidia gpu's like the 460 and 450 is in beta support through a patch for Total Media Theater 3 as detailed here. Total Media Theater 5 (they skipped 4) just came out, but I have yet to hear confirmation of bitstreaming support, however if it's not there, it's likely only a matter of time.

I am doing this now with a GTS 540. Bitstreaming works fine in all applications. The only exception I have found is that Powerdvd 9 doesn't bitstream blu-ray but Powerdvd 10 does.

I would recommend that you turn off any onboard audio. Also be sure that you use drivers 260.99 or later. And use the custom setup to make sure that
hdmi streaming driver is loaded. Once I did that I checked the windows sound settings and it displayed my tv as the sound device (?) but it works great.