I have an antec nine hundred with a gigabyte GA-X38-DQ6. The case has an HD audio connector and an AC97 connector. The manual for the motherboard says it can accept either. When I connect the HD audio, the sound through headphones on the front panel has a constant static/buzzing sound. The sound changes when I move the mouse or when the hard drive is being accessed. Seems like some sort of interference so I moved the cable so that nothing was near it. This didn't change anything. The sound from the rear headphone jack sounds just fine. In the BIOS azalia codec is set to auto. Any idea what is causing this and how I could fix it?