3d Tiled terrain

Question

I'm trying to create tiled terrain in 3D with XNA. I checked tutorials on how to do
it(Riemers and Allens). Allens tutorial has an exact result I want to achieve,
however I'm not sure about performance - it seems he is using single quadrilateral to draw
all terrain and process it with pixel shader, it means - whole terrain will be
processed each frame.
Currently I'm drawing a quadrilateral for each tile(Example) - it allows to draw
visible tiles only, but it also means that much more verticies need to be processed in each
frame and a lot of "DrawIndexedPrimitives" is called.
Am I doing it right or Allens way is faster? Is there a way to do tiled terrain better?
Thanks.