Flickering land shadows

[Devastat]

In my case the new patch did enhance the performance of the game a bit, tho I still wouldn't call the experience of flying over London and other big cities very enjoyable.

Anyhow there is one visual problem that really annoys me (already before patch) that shadows of the trees and buildings are flickering or wiggling quite badly. I wonder if anyone is experiencing the same?

My Graphics Card is Ati Radeon HD 5850.