Hi Querer,
Not as rediculous as you might think, some folks need 60fps for a smooth experience while others are fine with 30fps. When you are parked at a airfield and you pan your head left and right, if the the trees and buildings in the distance are stuttering then your experience may be less then optimized.
Note how the envirment feels while panning @60fps, if you notice a less then smooth experience at less then 60fps, you may prefer 60fps to anything less.
If you find that your frames are dropping down to 55fps and you realy need that extra 5 fps for vsync, thats where less trees/buildings or grass might be a casualty etc....
Furthermore the vram the sim needs can exceed your graphics card at max settings easily.
One other thing, use
FXAA in the nvidia control panel and the other AntiAliasing options set to aplication controlled or off, set in game setting for AA to off for better performance.
Black Death is under Extras/Tracks.
This may help:
http://forum.1cpublishing.eu/showthread.php?t=19819
See ya in the air!