I've got a brand new macbook pro maxed out with everything.
Running all the latest CC, and Lightroom ran fine on my previous macbook pro, but with this, the second I click develop, the CPU percent of lightroom goes way up and my fan spins like crazy.
I turned off all face recognition and such also....
First, try unchecking the option Preferences > Performance > Use Graphics Processor.
THANKS!!! Worked a charm!