I built a gaming rig a little short of a year ago, and while this issue isn't necessarily new, it is becoming much more prevalent.
msi P67A-GD65 motherboard
8 gigs crucial ripjaw RAM
msi N560GTX-Ti graphics card
using the motherboard's audio
It doesn't happen all the time but every now and then it will start giving this small stutter in the sound every ten seconds and the only way to remedy it is to restart the computer.
The glitch does sometimes affect the video, but mostly it's just the audio. Even making it go out of sync with the video.
I have updated all the drivers, defragged, virus-checked and I can't locate a cause or any other way to make it better. I barely use any of my 8 gigs of RAM or my 3.40 ghz of processing speed, and my temperatures are all ok. Sometimes it happens right at startup and once the glitch starts, it is computer wide. It is not tied directly to gaming either, it will start up sometimes just browsing the internet.
What you are describing sounds like (rofl) either a driver conflict or the sound device being defective. It could be either the video or the sound driver. In some situations the driver is in conflict with a service running in the background. If you have access to a sound card, install it and see if the problem goes away. If it is not that the driver is out of date (you report updating them) then trying to find if it is a service conflict is tedious. You would close all but the essential window services and then start turning them on one at a time after seeing if the effect was gone when they are shut down. There are inexpensive sound cards available. You don't need a good one to test the MB device. Many local small Comp. stores have used ones available. Drivers can be downloaded if needed. BTW I think the latest RealTek is ver. 2.66.