Its onboard HD3200 yes.
Video is fine with ati 9.10 and realtek 2.35 hdmi audio drivers
. I can get ac3\dts audio from the hdmi cable connected to "hdmi 1" on the receiver.
The problem is when switching to tuner, tv etc and back. The HDMI audio out is stated as "not plugged in" and ATI complains about a HDMI-DVI cable incorrectly. So realtek digital output is set as default.
Changing resolution or turning on\off tv and receiver brings it back.
Tried a vista image made before win 7 and it worked fine, ac3\dts output and the receiver recognized it fine after switching to other sources.
Spend a few hours with a clean image of win 7 and tried different combinations of ati\realtek hdmi drivers. Either would the screen be black or the hdmi audio was not plugged in. So im guessing something with how hdmi devices recognize each other that changed in win 7.