A budget OBJ landscape I got from CGT, a basic Landy 4x4 from some-when, a sky-dome from my archive plus a LOT of iteration gave two of the biggest Superfly renders I''ve ever dared run. Poser would not use my twin graphics cards, I had to resort to ''trad'' CPU cycles...
Note this uses the ~4MB OBJ mesh. My usual trick of ''displacing'' a low-poly base-plane with the supplied height map made the landscape impossibly jagged...