Heya, I got a radeon HD5850 I had alot of problems your having and I fixed a few of them. Someone mentioned depth of field messing the trees up like that, that is exactly right, took me forever to figure it out, play with depth of field off and the tree issue will be fixed.

The other issue I was having was with Morphological filtering (in the CCC) this was causing me to get glitches in the menus and cursor, when I turned that off my problems went away.

As far as the shadowing goes, it kinda just sucks...