I have that board.
Sound works just fine in linux.
If you really need to know if the problem is the board or not, follow these steps:
1) make sure bios is set to require keyboard and audio bios errors.
2) plug your speakers into the GREEN jack on the back.
3) power off, remove keyboard from computer, power on.
You should get an audible notification that no keyboard is detected. If you don't, RMA your board.