Another thing about the 74 minutes. That was for a larger radius than necessary and a smaller timestep than necessary - for a high quality video. With a radius

Another thing about the 74 minutes. That was for a larger radius than necessary and a smaller timestep than necessary - for a high quality video. With a radius of 10.0 and a timestep of 0.1 I get 186fps on the same graphics card - visually about the same speed as the youtube video.