You sure you didn't accidentally start a FRAPS record?
It might be a good idea to change the default key for disabling the mouse pointer, just in case.
Damn that was a good guess haha but alas my fraps folder was empty so whatever the reason behind that, unwarranted, drop it has only happened once.
Other than that it's pretty much fire, fire, and more fire that drops the framerate otherwise it's 30.
Also I really have to reiterate my gratitude Durante, the game went to a "won't even buy at sale" when all the horrible performance and technical issues rumors turned out to be true. Yet here I am, playing the game and loving every bit of it thanks to your fixes.