well all i can say is i tried once to write a true multi processer piece of code using c and mpi, using u.c.c. supercomputer (contains a feck load of processors) and i can say to write a multi core fiburnacci sequence generator was a frick nightmare. And thats an algorithm you’d bang together in about 20 lines of normal code, and one you probably learned in the first 2 months of programming.
I can imagine a state of the art 3d engine is going to scale up to a really shit hard challenging piece of coding. Although i have no doubt they will rise to the challenge, they have too.