Heightmap simplification

Well, i was thinking about a strategy to greatly simplify heightmap terrain rendering. I am currently creating an empty D3DXMesh object, then I use the D3DXCreatePlane function on it to create a patch of XxX. After I just need to set height values of Vertices. I wanna ask if the D3DXProgressiveMesh is really good implemented, i wich case i can subdivide patches(i was thinking doing subsets inside D3DXMesh), determining their distance, and set more or less vertices. Well right now, without any occlusion I got good performance, as i can use D3DX::Optimize caches-friendly functions. I wanna know guys if such a solution is viable inside a good engine. thanx. Cybird