I'm only running a single core AMD FX57 with 2GB RAM and a 9800GTX+ card on XP Pro.  The 767 is a challenge for frame rates for that system. What I'm finding with version 1.2,is that the integrated radar is a major frame rate hog. If you're running the radar all the time,try shutting if off to see if that gets your frame rates back to an acceptable value. Only 2GB RAM with Vista 32  may be an issue for you as well.