Same happens to me too. Radeon 3870 desktop graphics on Win7 64bit.
At first I thought it would turn out to be a 3870 issue. Seems it does not only affect hd3870 cards. Weird coincidence though, way too many 3870-s have it.
Reseted driver to factory defaults, no use. Fiddled with all the settings in the options menu, still to no avail. Turned off Vsync, no use. Im out of options for now.

Hunting google and forums for a sollution atm...
Will post if I manage to find a remedy somewhere.
edit:
I Found a solution \o/ FINNALY!!!!
http://www.gamesas.com/index.php?/topic/1257882-patch-1-unofficial-bugfix/
use this unofficial bugfix !!! this works!!
Indeed thats a WINNER!! Ya beat me to it dawg!

Thanks for the link!
