Onboard sound, only digital output (SPDIF) is used! No problem if going through WASAPI, AC3 and DTS are fine too. But if I play stereo audio (even fixed at 16bit) through directsound or waveout, random noises are poping out from time to time. Audio driver and MB bios updated! CPU: i7-920 Motherboard: GA-EX58-UD4P Win7 x64 Ent.