Some people all over the FS community appear to confuse the minimum requirements posted on the boxes of FSX. Some think that the hardware listed is what's really needed to run the sim at mid-high settings with enjoyable frame rates.
There is a distinct difference between running FS and actually enjoying it. Running is when your hardware is capable of actually making it work at its minimum settings while enjoying is when you're satisfied with the quality and frames of the sim.
Therefore, the hardware listed in the boxes of FSX is only what's needed to RUN the sim. If you read closely on the box you'll see a small text next to the hardware list that says "The above are the specifications a computer MUST have in order to RUN this game. Increased performance will be noticed on more powerful systems. Online/multiplayer requirements are not needed for single-player mode."