Hi,
I just got this motherboard in a HTPC build.
I could connect 5.1 optical SPDIF to my amplifier, it works fine.
I could also send the audio with the video through the HDMI but i could only send 2 channels, i suspect its my TV as the motherboard detects the type of monitor and i suspect its detecting 2 channels device hence only allows me to send 2 on the HDMI. however I could send uncompressed 24 bit 41khz Studio quality audio.
Cheers