Here's a thought, in the thread you've linked to the guys have suggested that it is probably the Creative X-Fi drivers causing the issue. So, I have 2 suggestions:
1) Try using a different set of drivers, such as the YouP Pax drivers, or
DanielKs ones (from experience I recommend trying these first). Specifically, you want to grab the 2 parts (
Here1 and
Here2) that make up the Vista install CD.
2) Your motherboard uses a Realtek HD audio chip onboard, which is actually a pretty decent audio chip. To rule out the Creative sound card you could try removing it, and use the onboard audio to see if you have the same issue. If you do try this be sure to download the latest drivers off of
Realteks site as the newer ones perform better. The one you want (after accepting the agreement) is the 5th option, which is the exe version of the driver.