Well I used to have this problem and it was VERY frustrating. Now I'm using the demo (I hope it works with the original game too). I'm using Windows Vista 64bit and a soublaster audigy 2 soundcard. What i tried was this:
I've right click the speaker button for the sound in the lower right corner of the windows screen and selected playback devices. Then I've selected speakers and clicked properties. And then in the advanced tab I used to have the default forma in 24bit 192Khz... I've changed it to 16bit 44.1Khz and it worked for me at least
The shuttering is greatly reduced. Plus the game becaume a bit less luggy.
I hope this works for others too.