should really get one with a dedicated gpu. the interface in max 2010 is more gpu dependent and looks like there are going to make max even more dependent on gpu so if you want decent performance get a dedicated gpu with at least 512mb of video memory
I would suggest generating erosion on the terrain using a dedicated tool like WorldMachine or Terragen or the like. This will make a splat map for you, which you can use in a Composite node as your layer masks. To isolate the RGB color channels you can use Color Correction nodes, or even easier just use a single OSL Uber…