CFS3 is so so (as released), maybe extensive community modding and official patch will improve it , but for now I'd recommend you to stay away from it. I think that the code isn't optimized enough (like MSFS2000 used to be), and even with GF4 you'll most likely see slideshow/stuttering time to time. Gameplay isn't any great neither, external graphics OK, cockpits average or worse, some cockpits graphics are either unfinished, or generic, or with glitches (like crosshairs off etc). I shelved the game, and waiting for patches/mods....
Get IL2 instead if you want a decent WW2 sim.
hope this helps
dave
... I forgot to add one last important observation about CFS3; the game locked-up/froze rock solid my WinXP rig with 5 minutes of running (no game EVER locked this box, have it about a year and has about 20 games on, incl. Il-2, MSFS2002, GhostRecon, OperationFlashpoint , you name it)... read some reviews on Amazon, it gets like 2 stars out of 5 or so.