The most important benchmarks are those that we can't print – playing games, listening to music and watching movies in a room set up to be as acoustically neutral as possible.
Here, though, we can show that there's no benefit to offloading sound processing in terms of frame rates any more, and using Rightmark's excellent Audio Analyzer tool shows us how close to the claimed specs the electronics are.
Far Cry 2 - Frames per second (higher is better)
RMAA total harmonic distortion (lower is better)
RMAA Dynamic range (Higher is better)