I have a Windows 7 Professional HTPC with an A10-6700 Richland Quad-Core APU connected via HDMI to an Onkyo 3010 AVR, which is then connected via HDMI to a Panasonic PT4000AE projector. All items are 1080p @60Hz capable, the Onkyo is 11.x capable as well. I have a 9.2 surround system.
I set my video output to 1080p 59Hz (which then always shows as 60 in the Control Panel for some reason) and then I use the speakers icon in the system tray to configure the Playback Device (the APU HDMI Audio) to be 7.1 with the fronts set to large. I never turn off the HTPC, but I do turn off the AVR and the Projector. When I turn them back on, the Audio settings have reset back to stereo.
What can I do to make my settings stick? I am registry savvy and have no problem making changes there or to any of the services if need be.