there is HDMI audio support, as well as a 3.5mm crossover cable, and 3.5mm audio input, and output directly on the card. But it takes some serious working to get all your audio over to the 2nd PC... my problem was splitting off my Mic to the 2nd PC, and getting the sound from games to carry over as well. With a USB headset (I use the Logitech G930) its been a serious endeavor trying to get it working in a way that sounds acceptable with out loosing audio or mic from my first machine.
With an analog 3.5mm headset I ran into a pre-amp issue. The game audio was 10 times the volume then the split mic no matter how I carried over the game audio, and the mic audio was SO low in volume that if I lowered the game audio feed that low so people could hear me talk on my stream you just wouldn't hear the game sound at all. Hence USB headset. My problem now is using Microsoft mixer to move stuff over again with out loosing audio from anything else...
In interim an analog 3.5mm headset could be plugged into a USB enabled audio mixer. all the audio could be sent to that, and output at the same exact levels to the 2nd computer. Even a non-USB enabled mixer would solve the problem, would just use more cables. Upside to a mixer is you can run a studio quality condenser microphone on a boom and sound like a BOSS! down side is it all costs lots of money. 50-100 for a good mixer, 100-200 for a good condenser mic (that's not USB) 30-40 for assorted cables, splitters, and adapters... could use your own headset still, and skip the condenser mic, would still cost you 100-150 dollars (US) or so...
Point Is just be prepared to mess with it, and maybe even drop some extra money to get it sounding right.
