just installed the nvidia gpu previously had dual 5870 from ati. i uninstalled and swept the ati drivers before the install
with my ati cards i could run the hdmi into my onkyo receiver and go into the audio properties and select 7.1 surround and al speakers would play perfectly. when i try the same with the gtx the options are there and i can select 7.1 but when you run the audio test it only plays the front two speakers. If you click next with the 7.1 selected the speakers make a god awful noise untill you select stereo again.
i did ty blurays and the ones i did try output perfectly dolby hd 5.1 but games like battlefield 3 dont like it used to..
I'm not sure what the combination was but I somehow got it working like a champ. Wish I knew how so I could help anyone else that might have this dilemma. I changed the bit rate, drivers, cables and tons of reboots with no luck. Came home and decided to try it again fired up the pc and it switched to 7.1 with no problems. Don't know how or why but glad it did. Thanks