The workflow I'm using, this only produces textures. The geometry is made on a normal plane that's displaced with a height map. In the app once the nodes are computed it's fast, but when you make a change to the parameters of a node, it recomputes that node, and if you're making modifications to a node that has other upstream nodes, it has to recompute those too. That's where things can get really slow, but the quality out of the box is so high, it's worth it.