[MonsterHTPC]

Save yourself the money and just ensure your soundstorm is setup to pass the signal through.

I forget the sound storm settings, but sound storm has the ability to take multi channel sound and encode it into a dolby signal to send over spdif. Just look around and make sure there aren't any settings turned on that would do any processing to the signal before sending it out. Would hate to have an app decode the audio into two channel stereo then the soundstorm reencode it into dolby. Check your BM settings and see that they are set for SPDIF pass through etc... and you should be fine. Unless you are using analog outs, you don't need the upper two versions of NVidia decoders.