no. you want good single threaded performance and that cpu just doesnt deliver it, you would have done better buying a phenom 2 960 and saved money to boot.
fsx only needs a p4 single core to max it out cpu wise so 7 modules/cores/marshmellows will be sitting idle...
gfx? you dont need that much either as the game is designed to run on very old hardware... yes you can mod it up with dlc but you still gonna be hard pushed to max out any midrange gfx card.
you would get a little better cpu performance from an intel part. but really the difference will be minimal, because the initial requirements are so small.
if you built this system specifically for fsx then you wasted your money...
also buying a part that is really for a server and not built for gaming is a waste of money also as your never gonna see its potential fully realized... as i said a p2 960 would have been a better buy.
but hey you were probably told not to buy it by plenty of other peeps so i wont bang on about it, coz your not likely to take any notice anyway...
have fun and keep an eye on the electric meter...
*edit*
if you haven't received the cpu yet then cancel it and order the phenom 2 or if you have , dont open it and just return it.. you dont even have to tell em why your returning it as you have 28 days in which to change your mind about any purchase from the web.
http://www.tigerdirect.com/sectors/help/return.asp