I hadn't been using docker on my mac for a few weeks, and when I fired up the old containers this morning after updating Docker, I found that it no longer had one CPU going at 100% while my processes were idling as it did before, and some very high CPU usage during more demanding tasks. It now seems to behave like it does on Linux.
I had given up on docker on my mac, and instead ran it inside an Ubuntu VM on my mac, but this is much better. If you had given up on it too, take another look.
Some research reveals this; they've been focusing on fixing things:
https://docs.docker.com/docker-for-mac/release-notes/#docker...
https://github.com/docker/roadmap/issues/12