[aasasd]

Regular Ruby 2.5.1. I do have a throttled CPU due to no battery in the MacBook, but I still have Python and other stuff to compare, and Brew (or Ruby) definitely does something wrong on my machine. It's hugely CPU-bound without a particular reason for being so.

[wilg]

Weird. I'd guess Brew because MRI Ruby tends to have pretty good boot times.