I have a soundcard but I was curious to try out the HDMI output on my video card (2 gtx 580s in sli). SO I installed the driver and tried skyrim.
It worked fine the first time, but I noticed updating the driver disabled sli so I re-enabled that. I also noticed it reset my AA settings so I turned those back on. After doing so Skyrim would freakout. The menu screen would come up fine, as would the loading screen (which is rendering 3d). But once the game started the display would alternate on and off every few seconds. The fps was low about one frame every few seconds, and geometry would randomly disappear.
I had the hdmi plugged into the secondary sli card. I went back to using the soundcard and the game was still messed up. Then I disabled AA(anti aliasing), and everything worked fine. Whenever I tried to turn it back on the game wouldn't work, but disable it and it worked fine.
I then did a clean reinstall of the drivers (without the audio driver). During parts of the reinstall, the graphics display was corrupt. It showed vertical lines of random color. After the driver reinstall everything worked right, however I saw that windows then installed about 8 copies of the nvidia hd audio driver at once. But everything worked fine after that (though I went back to using my soundcard.) Both SLI and AA were working fine again.
Anyway I post this as a little word of warning that Nvidia doesn't quite have their audio act together, and as a question: Does anyone have any ideas wtf went wrong? and how I could use Nvidia hdmi audio output without issues?
I'm using the DVI output to reach my monitor, so maybe that's an issue?