Probably depends on the resolution -- I've found a good GPU-based CG implementation can chew through moderately sized problems faster than multigrid. I would al

Probably depends on the resolution -- I've found a good GPU-based CG implementation can chew through moderately sized problems faster than multigrid. I would also imagine the blog author could get away with some fairly loose tolerances on the Poisson solve (at the cost of some compressibility) and still have the motion look great.