A while ago I owned an Nvidia card and had trouble with this game...but I found running the game on its medium (mid) or low settings would stop the lagging and sound problems.
If the mid settings don't help performance - Click the Custom check-box and use the settings below
Blooming = low
Shadows = off
Vegetation = low/mid
sea = low/mid
Antialiasing = low/mid
Distortion = off
Fur = on
Also using the "-minspec" handle on the shortcut to the game also helps....to do this:
1. Right-click the game shortcut (either on the desktop or start menu) and click properties.
2. In the Target box click after what is written....so after the end "....press space to leave a gap and then type in -minspec....then click ok.