I had alot of sound problems with onboard, then I got a Audigy X-Fi Music that was on sale for $100. Fixed all of my 3d sound problems with Oblivion. I did have a few problems at first, but it was because I needed to go into my bios and set my onboard sound from depends to completely off. So if you have added a sound card, make sure that onboard sound has diffenatly been turned off.
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