same Problem here ...
tried another sound card (on the MB) - didn't help. Original sound card is M-Audio (no official
driver for Windows 7, with the vista
driver).
it crashes most of the time when two apps are running and one of them is a sound-app (browser, audio player, videoplayer). No blue screen, nothing in event viewer, no crash dump ...
Windows 7 x64; i use SPDIF on both SC; Phenom X4 on GA-770T UDP3
edit:
ITS NOT A Windows 7 PROBLEM, its actually a some kind of hardware problem. I tested the same system with XP - same problem. IDE, AHCI mode ... doesn't matter. Microsoft
driver, ATI driver ... the same.
Everytjing in BIOS is by default.