[lch]

I think that most of those settings will have very little effect on the game at all, if any. AFAIK it utilizes OpenGL for cross-portability, no Direct3D. AA/AF/mipmap stuff is probably only effective for 3D models, what Dom3 is lacking. Graphics-wise, Dom3 is like Duke Nukem 3D: The terrain is in 3D, but units and environment objects and so on are sprite graphics in 2D. Maybe the battleground will look a little nicer if you fiddle around, but that's probably all that will happen, and I even doubt it.

Those two OpenGL settings sound that they might be effective. But it's not like the game really needs buffering for the graphics, this is no First Person Shooter. In case the framerate is so bad that the battle replay is stuttering (??) this might help a little.

More or less the only thing that will make the game run better: a faster CPU.