FSX: i5-750 or i7-860?

go with the i5-750

FSX can and does use hyperthreading.Both of those CPU's will however run FSX well.The best and most common CPU's to use for FSX are the Core i7 920 or newer 930 model or the other higher end models up to the beefiest,best (and costliest)one of them all which would be the Core i7 980X.
Forum user Computronix is the expert about FSX on these forums.If you do a search (with his username) you will find his posts here.
Here is one link (where I linked a couple of his posts)

http://www.tomshardware.com/forum/285919-28-computer-hu...

on this post forum user arthurh posted a nice link to a company which makes and sells FSX systems that shows the relative performances of components.
It seems to be fairly accurate although not comprehensive of many components.
It would have been nice to have more CPU's listed etc.

All I want is a comparison of i5 vs i7 for LGA 1156 ONLY. Nothing more thanks!

go with the i5. the i7 is the same chip but with HT.

HT is not going to make a difference in 99 percent of games, and when it does its not going to be huge. by nature it is not very useful with the way games are processed.

It does make a difference in FSX. I'd get the 860.

For almost any other game, I agree that it makes little difference, but FSX is one of the rare exceptions.

If you have already bought a LGA 1156 board I agree with cjl above.The 860 will be superior in performance.FSX utilizes extra threads and cores.However the i5 750 does make a great budget FSX build.