Keep in mind if you got a soundcard, disable HD Audio (onboard audio) in the Bios. A month ago I was having some whack sound issues (mostly left speaker cutting out) and wanted to get away from the Creative Labs X-Fi Fatality anyway that I've had for years (and worked until lately) so I picked up an Asus Xonar DXT. Great card for the little cash it costs and no gimmicks, unlike the X-Fi. Anyhoo, the issue appeared again and upon looking, somehow my Bios was reset so my onboard audio was enabled. Once I disabled it the issue went away. This must have been the issue with the X-Fi and not that the card was failing which is what I suspected. So to lessen the chance of a conflict between onboard sound and a soundcard disable the audio in the bios.
Most don't run soundcards these days anyways so it's all probably moot point.