I recently bought dx58so w/ core i7 920. Had problem for few days with no sound issue that is popular with this board. First I tried to use analogue connectors (Green, Yellow, Black cable), I could not get a sound from one speaker whatever method I use. And for digital (optical cable), I could not get any sound at all.,
Anyway, here is my setup and how I resolved them:
Core i7 920
Windows 7 Beta 64 bit
Logitech 5.1 THX Dolby Live system.
Latest Bios and Audio Driver from this site.
1)analogue connection: I keep on trying pulling the one of connector out and plug it in again until both speakers had a sound. ( one connector for both speakers. eg: front right speaker & front left speaker) This is ridiculous but worked. I see there's similar problem with my front Headphone jack too. Sometimes audio manager says it's unplugged even though it's plugged.
2)digital connection: I had no sound from my 5.1 ch speakers what so ever. First, I thought I had to connect the board w/ some cable or realtek chip is broken or something. However, I decided to uninstall and reinstall the audio driver as a last resort. My speaker system was ON and optical cable was connected w/ PC when I reinstalled the drivers. After reboot, Realtek HD audio manager tab shows "Digital Output(Optical)" and boom, it is working fine.
Hope this helps some people. Good Luck.