i would guess the audigy simply because it i so much bigger, and has more stuff cos its an add-in card. like i think you said when referring to getting the "true processing power" you have to watch the MCP-T boards because some manufacturers use different codec chips along with the APU, like the Gigabyte 7NNXP uses the Realtek ALC650 AC97 codec, meaning to bypass the realtek chip and use the full power of the APU, you have to use the SPDIF ports (therefore using the correct speakers, if you want to use dolby digital stuff. using the analog outputs switches to the realtek codec