I stopped using FSX due to continuous OOM when combining glass cockpit jets, add-on weather, and a frame-rate-eating scenery package.. When I moved to X-Plane I immediately entered a relatively stable platform, excellent scenery, the opportunity to build my own world via mostly free (and very well created) airports and scenery and, best of all, the IXEG 737-300.. I have never had a problem with system resourses.. I fly every day, and my circuit is all over north america, sometimes also to Europe. Everything functions better than I could hope.. And the 737 is absolutely amazing..
Like Jan said a while back, this experience is sure a lot more immersive than watching TV.