My understanding (I am not an authority) is that for a long time, it has taken Pixar roughly an equal amount of time to render one frame of film. Something on the order of 24 hours. I don’t know what the real units are though (core-hours? machine-hours? simple wall clock?)
I am not surprised that they “make the film fit the box”, because managing compute expenditures is such a big deal!
(Edit: When I say "simple wall clock", I'm talking about the elapsed time from start to finish for rendering one frame, disregarding how many other frames might be rendering at the same time. Throughput != 1/latency, and all that.)
replies(6):