What audio chip is on that board...sounds like a driver issue to me. Did you check with default Windows drivers?
My mouse literally skips around the screen when it is at its worse. 7.1 CH HD Audio with Content Protection (Realtek ALC898 Audio Codec) I am using the windows default driver.
Did you try the Realtek HD Audio drivers. I have similiar hardware and never faced problems with these drivers so far.
Signed into my admin account, uninstalled all audio devices, installed the driver, restarted. Checked device manager for any devices that needed installed, none. Back on my standard user account and no playing the waiting game.
And its back. Well, back to the well known and loved Windows 7! ~ed~ Maybe another temp fix. Installed the asrock release for my network driver.