i didn't look too closely at the rest, but i recall seeing something about a ground chunk size of 30m and a scene size of 4000m, which would work out to 4000/30 = ~133 quads across. 133 x 133 = 17689 quads before culling = ~4422 quads after culling = ~8844 triangles visible. its unlikely they render it as individual 30x30 quads.although they did say its was unoptimized. so they're drawing an unoptimized ground mesh of about ~9000 visible triangles on a MIPS, which doesn't seem like much work to begin with. and then the algo cuts the framerate in half. doesn't sound too promising.

OTOH, i'm drawing ~4050 visible ground mesh tris (+ additional terrain) at a rock steady 62.5 fps. so maybe its doable.