in the F15 it appears at approx 170knts.
But since it was a frame killer with my old AIW 9800 pro.. I turned it off.
(old system P4 2.8/3.2 w/1gig)
The best settings I got using that system was using modman and load the
p4 profile. Then I went back into lockon and set water to medium, haze to basic and heat blur off, scene's to med.
I then installed, sun, moon mods. and bobo cops 3.1h mod (on my site or lockonfiles.com)