I know i'm still having problems with battles but I've not had any issues with the campaign. If you have Nvidia like i do you should be able to right click on your desktop and select NVIDIA Control Panel.
From there on the left hand side of the screen click on the "Manage 3D settings".
The page that comes up will have 2 tabs. Global Settings and Program settings i would suggest using the program setting so as not to mess up anything =)
When you click the program settings tab you should select the program to customise.
The setting called "Antialiasing Mode" should be set to override (I think) and then the next setting below this the one with numbers should now be available to change.
Many people say different settings so all i can suggest is to try it out one at a time. Also sometimes in the options menu of the game lowering the campaign map resolution helps (at least it did for me)
Hope that works.