Upgrading CPU Mostly For Gaming (FSX) Any Suggestions

i am upgrading my computer which is going to be specifically for gaming, FSX. i really need help in deciding whether i should get an e8400/8500 or a Q9450????? i mean i know i will definatly be better off with a qx extreme, but as most of you know they go for like $1000 so i cant really afford that right now. I really need some suggestions thanks a lot. by the way, from reading other post, they say that i'll probably be better of with an E8500 because FSX doesnt really utilize four cores, some even argue that they use 2. anyways i would really appreciate comments on which upgrade would be better for FSX thank you.