commercial signs and objects flickering

Guys when i play rfactor i sometimes see commercial signs or objects flickering.
What can i do about it??
Im using a nvidea gts250 card
One of my frieds suffer from a weird problem that he pulls all graph settings to full, full aa and filtering, he has about 120-150 FPS, but for example in LeMans he cnnot see lots of objects for example trees, buildings and such... He has an amd phenom proc and a hd5670. Can you help what can be the matter?

Thx :)
Top Bottom