I've been playing Oblivian for quite some time (Win 7 64) with unofficial patch and a few texture mods. I do not have that problem at all. I have self shadows,shadows on grass, tree canopy set to off.Shadow filter on higher. HDR off and 4x anti aliasing. There are several forums (Oblivian Nexus, for one) you can look at...just do a search. Also, don't know if it matters, but I have the DVD GOTY version, not Steam.