My system specs are,

CPU - i7 960 @ stock speed
GFX - GTX470
Memory - OCZ 6gig DDR3 @ 1600mhz
Boot Drive - Corsair F60 SSD
FSX Drive - WD 150gig velociraptor
1tb drive for photo scenery
XFI Extreme Music ( Using Creative Alchemy to force fsx to use openal as it works with win 7 but not vista )
Windy 7 Ultimate x64

Its not the fastest pc but i have tuned fsx to the way i fly which is slow and low and high and fast so i do use more than one fsx.cfg :)