After all, did you also have checked your mobo's BIOS settings? (default values, etc,...) Though on my machine i cannot verify any
difference in the running behavior but other people have reported that a "PnP OS" when it is set to "YES" or "enabled"
in the BIOS has confused the IRQ settings for the BIOS will not control possible IRQ conflicts etc,...
So check all audio control settings in your BIOS, and also this "PnP OS" thing. And if nothing will help
remove ALL unnecessary cards, and other stuff from your board and try it again. ANd no "crazy" overclocking experiments ;-)