I find that it runs quite well on my not nearly new PC. Just like FS9 needed alot of tweaks to fine tune it, the same is true with FSX. After applying a few tweaks and finding the sweet spot for the settings I get an average of 20-30 fps and sometime even higher. All this without turning off a single background process. I imagine after I whittle those down it will run even faster. Most of my sliders are set mid to high.