Large TIFFs – I use this heavily with my IMAX project In Saturn’s Rings, do take time to start in MP. The more memory per thread you can hit them with helps a lot as well as leaving extra memory available for OS. SSD drives helps yet again for assets and caching.
I use to have to run with MP turned off on a 24GB RAM system. I have 64GB right now, run 6 threads with 6 GB per thread and things are good and stable. But I have some comps with 30,000 x 15,000 pixel TIFFs in 16-bit. Those take a while to MP render and even just open/preview.
A film is – or should be – more like music than like fiction. It should be a progression of moods and feelings. The theme, what’s behind the emotion, the meaning, all that comes later.