I have the same board, but this didn't work for me. Still no audio with 6.4, so I had had to reinstall the ALC898 driver from 6.2. The only problem with this is that I get a crackling, static burst every time I load websites, and when I send or receive emails.
MultiBeast for Mavericks works for 10.9.0, 10.9.1, 10.9.2, 10.9.3, 10.9.4...Thanks!!
Does it work with OSX 10.9.3?
Sorry for newbie question..