Check out
http://rog.asus.com/forum/showthread.php?14986-G75-audio-system-bugreport&highlight=audio+report. I recommend reading this thread from the last page backwards, so you get the latest information first. @c-man has a guide to configuring the VIA driver with a link to that thread in his signature, so check out his posts.
A clean installation of the driver may be important, rather than just installing over the top of your current VIA version. Here's what I'd do if I owned one:
1) Uninstall the current VIA driver from "Control Panel - Uninstall a program".
2) Reboot into Safe mode and run Driver Sweeper to remove any VIA driver remnants. Consider following up with CCleaner to clean up the registry.
3) Reboot into Safe Mode and install the recent VIA driver.
Booting into Safe Mode will disable other running drivers, such as Anti virus, that may interfere with your VIA cleanup and installation.
G74SX-A1 - stock hardware - BIOS 202 - 2nd Monitor VISIO VF551XVT