I have an 8 channel HD on board realtek audio chip, and it went from working wonderfully to popping, and cracking. Well, I tried using a different media player, uninstalling the drivers, then reinstalling, and checked all my connections to make sure my high powered sound system wasn't starting to act up (that would have been really nice, as it cost me a mint). Well, I then started thinking "what have I changed recently? I had undervolted my CPU using RightMark, and stress tested my system for multiple hours without any errors or BSOD's, passing all Orthos test using blend mode. But, this was the first time I had actually used a media app since performing the under volt. Well, after changing my CPU back over to "high performance", and turning RightMark off I stopped getting those annoying pops and cracks. This kind of annoys me, as I was getting other wise good results from the undervolt, and everything else seemed stable. Also, while I've worked on, built and modded pc's for a good amount of time now, it still took me about an hour of trying different things before I remembered that my little adventure in undervolting might have been the culprit. I could see an inexperienced user pulling their hair out over something like this and even going so far as installing a sound card thinking their audio was corrupt, before they would ever think it had something to do with undervolting.
So you undervolted and underclocked, or just undervolted at stock clocks? Have you tried underclocking without undervolting or undervolting without underclocking?
Undervolted at stock clocks. I didn't want to underclock, as I was trying to maintain performance, while lowering temps. The undervolt seemed to have worked swimmingly until I noticed the audio problem. I was running at about 5-6c lower temps at idle, and 8-9c lower temps under full load, while cpu-z, orthos and other programs reported my CPU as running at it's stock clocks. I might try some other test, like undervolting, while slightly overclocking, or just going back to the 20% overclock (with stock vcore) I was running at before deciding I didn't need to overclock. hopefully this thread will help someone else who encounters the same issue.
This shouldn't be happening. Its probably noise from your cpu vrm circuitry. Your sound chip, would not directly run off the same power. The cpu vr has its own 8/4 pin 12v source from your psu. http://en.wikipedia.org/wiki/Noise_%28electronics%29
Another m/b exactly the same, probably won't do this, but could.
Main article: Burst noise
Burst noise consists of sudden step-like transitions between two or more levels (non-Gaussian), as high as several hundred millivolts, at random and unpredictable times. Each shift in offset voltage or current lasts for several milliseconds, and the intervals between pulses tend to be in the audio range (less than 100 Hz), leading to the term popcorn noise for the popping or crackling sounds it produces in audio circuits.