New Gigabyte Z77X-UD5H and screech of death

My Asrock Z68 Fatality died utterly a few days ago. One evening I shut my PC down without issue, then next morning, nothing. Yanking everything from the board showed no power going to the board at all. And old mobo I had lying around powered fine. Only 10 months old. Up until that point it had performed flawlessly.

It being last saturday, and me generally being impatient and not wanting to wait the 3 day weekend plus x amount of time to replace, I ran out to a local high end dealer and got a new Gigabyte Z77X-UD5H mobo. http://www.gigabyte.com/products/product-page.aspx?pid=...

I ended up reformating and reinstalling Win7 64 bit. since then I have been encountering the dreaded 'screech of death' often associated with Soundblaster cards (but not exclusively).

It happens at random during 3d applications mostly. For those not familiar, your PC freezes, and random static or looping sound plays through your speakers until you manually shut it down.

My current theory is that this is caused by the onboard sound hardware. I disabled it in Windows and ran for about 90 minutes last night without issue using a USB headset. Not definitive I know and I will continue testing.

My videocard is a Radeon 6970. I don't believe its related to that directly. I ran the full 3dmark (basic) test without issue.

The question is, if it is the onboard sound, is this an IRQ mismatch or other resource issue? Any suggestions on how to resolve it? I don't want to go through the pain of trying to get a seperate sound card.