Comment 4 for bug 278786

To Shaun:
Just a same here. Only I also have choppy unbearable sound. Did you also have choppy sound? If so how did you fix?

Anyway, you'll find that the AC97 problem is linked to the AC97 capture. If you show that device and then mute it (under the recording tab) the ac97 slider will have no spine chilling squeal. As for startup noise, it must have something to do with starting alsa and enabling AC97 capture.