I was one of the users that suffers from high CPU demands due to sound (though I don't know why, you'd think a core2 would be alright...). I started playing with nosound and that helped with the CPU load a bit, but still wasn't great. I updated to the beta patch, which claimed to resolve sound issues, and though the CPU load is MUCH BETTER, the sound will cut out every minute or so after a certain point in the game. There doesn't seem to be any specific trigger, it just mutes for a few seconds then comes back. Sound settings on low, onboard sound. Let me know if you need more info.
