yup, you've also got to remember that a final frame will have been rendered many times. Each and every asset, animation, lighting, texturing sim and final comp

yup, you've also got to remember that a final frame will have been rendered many times. Each and every asset, animation, lighting, texturing sim and final comp will go through a number of revisions before being accepted. So in all actuality that final frame could have been rendered 20+ times. VFX farms are huge, In 2014 I worked on one that was 36K cpus and about 15pb of storage. Its probably now in the 200k cpu mark.