My system runs this fine..

[SacaSoh]

i5-760;
HD6870;
4gb ddr 1333;
2x 7200rpm hd's (1 for windows, other for installed games);
Freetrack - ps3 eye;
All stock.
1920x1080

Bought from justflight yesterday, tested today... in the first run it ran with heavy stuttering, all medium except building detail and building density (or whatever it is called) that are on low, 2x AA. After that i ONLY changed the ";ProcessAffinityMask=3" to "ProcessAffinityMask=15" and the game now is smooth. I tested over land and water, with 6 x 6 fighters and it only slows down when you're flying low and it access the HD to load buildings and trees.

I think it need a lot of optimizations, but i guess it won't take much time to make it run better on lower specs PC's.
Sry for bad english.