Just a small update for you, our compatibility team is looking into these issues, a couple of them could actually be related..
We have passed along a great deal of information to Nvidia for review, and we are continuing to work on recreating these other issues.
Things to make sure of at this time, or things to get you into the game while we continue to work on these issues;
--Nvidia, if you are having issues we recommend using the beta 81.87 drivers from nzone.
--Dual core, try the dual core workaround located in the hot topic area of these forums.
--Sound, if you disable sound and your issues go away, things to make sure of are the following:
1.) In the audio section of the control panel, please make sure you have your audio card selected as your device and not your modem or some other device.
2.) Make sure you have your manufacturer's latest release driver for your audio card.
3.) Make sure you try both Hardware and Software for audio inside the game's audio section.
4.) Try lowering your hardware acceleration for your sound card to see if this improves your situation.