I've been hacking at an architecture change (probably going into X-Plane 940) that allows X-Plane to build 3-d forests on an arbitrary number of processors.
(Currently X-Plane 930 can only do this on one processor, albeit not the processor you use to draw the world and fly the plane.)
Going to KBTV with the highest tree settings on an 8 core Mac Pro we get these numbers for "preload" times (that is, the time to pre-generate all nearby forests, which is basically a memory-intensive operation (since the trees are so simple):
- 9.30: 1 core, 20 seconds.
- 9.40, OS allocator: 8 cores, 40 seconds.
- 9.40, NedMalloc: 8 cores, 2 seconds.