but I wonder if Demigod uses multiple cores (SupCom didn't)
Yeah...that was one thing I was going to mention. I've enjoyed every Gas Powered Games release I've played, but sound always seems to be an issue. This and the SupCom games are the only ones I've run on my machine that have sound issues.
For me, I get sounds that are all out of whack in the opening video (can't hear the narrator for example) and I get all kinds of crackling and popping when large battles come together in game. Other than that, it's smooth sailing.
Machine is definetly above spec.