The work is always divided per frame yes. Everything is baked so that happens easily even with water simulations, they’ve been reduced down to some form of geom

The work is always divided per frame yes. Everything is baked so that happens easily even with water simulations, they’ve been reduced down to some form of geometry or something similar that can be rendered frame by frame. The VRAM is indeed one of the main issues. But as someone else I believe cost per final pixel is still lower in CPU. That was particularly true during the GPU shortage.