You'll get that speed situation in all cases of polygons which are stacked behind each other in the 100s where you put priorities, as the object's priority is possibly not in the same order as the objects themselves are in the Direct X Z buffer. So as long as we can't access the z buffer, we can't decide who get's added in first, or maybe we can figure that out from the code. But if you add the objects in random order and put random display priorities, that should yeld slower (if my logic holds). That is why in my terminal system I draw each layer at a time from furthest to nearest.