Playing onboard SoundMAX digital audio over NVIDIA GTX 260 via HDMI

Do you not have an "HDMI" option in your playback devices? Also have you tried checking for a SupremeFX (the audio chipset on your mobo) control panel? With my back-up dual core rig running a 650i board with Realtek audio, I have to go into the Realtek control panel to switch from analog to internal SPDIF in order to get sound over DVI-to-HDMI...

Thanks for the response, Lamiel. There is no "HDMI" option in my playback devices. I have tried checking for a supremeFX control panel (but I thought supremeFX was a soundblaster XFi application) as well as a SoundMAX control panel, and can find neither. I believe I have the most recent update for my soundmax dirvers (6.10.2.6480, windows update is up to date), but if you have found a link to a more recent version or control panel, let me know! Other suggestions anyone?

Does anybody have any other suggestions for how to direct sound from my onboard audio to my DVI out on my Nvidia soundcard? How do I make sure the physical connection is appropriate? If I need to change a setting in windows, how do I do it? There has got to be a person out there who has done this, otherwise there would be no point in this video card being shipped with audio-over-DVI-D-DL capability.

Cant say anything for your exact setup, but for mine (running Asus p5ql-e and BFG gtx 260 maxcore) I used a cable to connect the audio from the card to the mobo like you did, then I had to turn my sound output to digital in the bios. It also had an HDMI setting in the bios itself, but as long as you can even change it to spdif it should work fine because your 'tapping' into the signal. One other thing to check - especially since your DVI-HDMI converter was purchased afterwards, is that your converter itself can output audio. The deal here is there are more pins of the DVI end than HDMI obviously, so the audio signal is sent through extra pins in the dvi end to the hdmi end (basically its only meant for video, but since there are extra pins on the dvi end they simply run the audio through these to match up with the HDMI audio pins cause, why not). HOWEVER, if the manufacturer of your converter was lazy or cheap, they may have not bothered to hook up the extra dvi pins to the audio portion of the HDMI connector - IE your audio may be getting to the DVI-HDMI converter but since the audio isnt patched through, you dont hear it - may be a long shot but you might want to try a few different converters. (My card didnt come with on either but I had an old ATI one kicking around)

Just checked my bios (took picks but am noob at posting them so....)
anyway - under the 'Advanced' tab i had to turn high definition audio on
I then had a "SPDIF_OUT Mode Setting" with two options - Spdif output (which would send signal to my digital out on the rear of the mobo) the other option was for HDMI Output with the following description "If the VGA card has HDMI output and need to use SPDIF signal from SPDIF_OUT header, you need to change to HDMI Output mode for HDMI audio output" - word for word - I would hunt in your bios for something like this as your mobo is fairly new - I know you stated there is nothing, but not sure what else to say. No other options come up when you choose digital audio? My suggestions are try a different adapter or two (that for certain pass audio through) try to find the digital audio/hdmi setting somewhere in the bios, and make darn sure your cable for audio from your gfx card is connected to the right header for spdif. Hope this helps