Try setting the game's affinity to one core and see where that gets you :)

Try this:

http://betanews.com/2011/03/07/tip-use-runwithaffinity-to-restrict-apps-to-specific-cpu-cores/

especially this section:

"If you're familiar with the command line then you'll probably know that Windows has a built-in tool to set the affinity of a process already. Essentially you'd create a shortcut to run a command line, something like "c:\windows\system32\cmd.exe /C start /affinity 1 notepad.exe," where the number following "/affinity" tells Windows which core you'd like to use."

I am not really sure, I figured that article would have its information right...

Tried setting the game's compatibility to Windows XP Service Pack 2 or 3?

At this point I'll recommend writing to Support and maybe saving a save where these issues happen because I have no idea on how to proceed :/