Try these settings:

Terrain Distance to minimum, all shader effects ON *except* for Full Screen Glow, max textures, no multisampling/anti-aliasing, no anisotropic filtering. Make SURE you have at least a gig of physical RAM.

I would suggest as low a resolution as you can put up with, UI Scale is a wonderful, wonderful thing. Played WoW on my PB15" for 8 months on a 9600 mobile with those settings - worked great except in mass PvP or MC. Now I rock a 7800GT on a gaming box, but the choice is up to you.