Here some tweaks to improve framerate.

[Feathered_IV]

Huge improvement on a Q6600, 2gb DDR2, GTX260 low end job. Using a lower res than desktop but getting playable 35-45 over land with shadows on, low trees and medium shading. Previously I was getting 7fps. still stutters a fair bit down low, but the 8gb ddr3 that I've got on the way aught to look after that.

One thing though, I notice land textures are very blurry at altitude. Would disabling some part of the mod fix that?