Many thanks for your comments, my system is not very recent but with quality components and fine overclocking. The specs are :XP-SP3, EVGA Motherboards 680i , Intel Core 2 Duo E8600@4 Ghz, 4 Gigas Memory with FSB@1333 Mhz and a Geforce GTX275, Monitor Dell 24'' and track-IR 4. When flying at a lower altitude over city the FPS can drop to 30 FPS ... But mostly is 60 FPS and X-Plane is tuned with not all parameters to High of cours. But when you compare to FSX is a dream and I think the future for X-Plane is bright Have a good flight 8)