Lighty;
In FS2 the game looks choppy as hell to me when it dips to 30fps.
Being used to 85 FPS Solid everywhere else (85hz refresh and that's what most of my games play to in XP now heh).
Generally speaking the game annoys me the most when the FPS is flicking between 29-40 FPS.
Simply because of the amount of slow down in my turn, the ability to predict flight patterns, the ability to hit accurately, and my ability to gain aspect lock (I mean in 85 FPS on Vanilla FS2 I can lick a friggin helios on a myrm if they're not pure doggying ME (though if they're doggying someone else then I can) -- you've seen my do it ffs

)
I *Know* the difference.
Whether I can see it or not, I'm not so sure, but my dodging ability also seems to be effected by FPS.
As does my ability to compete in Neocron.
....Heh.
Whether or not I can SEE the difference ...like I said, I don't know...
I sure as hell know the difference though...