There are 20 cube models at level 1, then each of those is divided into 20 for level 2 (400) then each of those is divided into 20 at level 3 (8000) and then each of those into 20 at level 4 (160000). That's a lot of RAM :-) I think I stop at 3, which is 8000x24 vertices = 192,000 vertices and 48,000 faces. At level 4 that would be 3.84million vertices and just under a million faces.
Press H to bring up the hud and it'll let you know.
Jim