From:
http://www.guru3d.com/article/geforce-gtx-580-review/5

"What is also good to mention is that HDMI audio has finally been solved. The stupid S/PDIF cable to connect a card to an audio codec, to retrieve sound over HDMI is gone. That also entails that NVIDIA is not bound to two channel LPCM or 5.1 channel DD/DTS for audio.

Passing on audio over the PCIe bus brings along enhanced support for multiple formats. So VP4 can now support 8 channel LPCM, lossless format DD+ and 6 channel AAC. Dolby TrueHD and DTS Master Audio bit streaming are not yet supported in software, yet in hardware they are (needs a driver update)."

From:
http://www.anandtech.com/show/4008/...force-gtx-580/4
"NVIDIA slightly revised their display controller for GF110/GTX580; the good news is that HDMI 1.4a is supported, the bad news is that full audio bitstreaming is not supported so it’s the same as it was on the GTX 480: 8 channel LPCM and lossy audio formats like DD+ and DTS. This actually caught us off-guard since we were expecting the full GF104 treatment here, but it just goes to show that this is a GF100-derrivative after all. Unfortunately this also extends to the number of displays supported – NVIDIA still only supports 2 displays on one card, so you need to run in SLI if you intend to take advantage of 3DVision/NVIDIA surround across 3 monitors."