ios Build Machine Specs

We're trying to determine what build machine we should get. I've been unable to find these answers in the documentation or on the forums. Basically, we're trying to find out if it's better to have more cores or faster cores. From what we can tell unity doesn't take up more than ~10% of our current 6core machine and not much more than 2 GB of ram.

There are two flavors on the store at the moment.

6 core 3.5 GHz
12 core 2.7 GHz

1. Is the asset import process multithreaded?
2. Is the ios/Android build process multithreaded?

https://www.apple.com/shop/buy-mac/mac-pro