TLDR; An old 2013 2.3GHz quad core Macbook Pro 15″ w/ 16GB running Sierra (10.12) is as fast as a 2018 2.6GHz 6 core Macbook Pro 15″ w/32 GB under Mohave (10.14). A Mac Mini 2018 (32gb) running Mohave is 21% faster than both.
My trusty 2013 15″ MBP has been a reliable workhorse for a range of development tasks, but as we have moved to using Docker in our dev environment, but with only 4 cores, 16GB, and a 500GB SSD, I considered both the 2018 Mac Mini and an Apple-refurbished 2018 MBP, both with 32GB RAM, faster processors, and 1TB internal SSD.
Admittedly, I had visions harkening back to 1984 when, as a grad student/developer, I hocked the farm to get one of the first IBM “AT” computers to hit Palo Alto, and watched the compile times for my educational app plummet from 20 minutes to about 4 minutes.
I even convinced myself I could tolerate the MBP touchbar / trackpad / keyboard since the vast majority of the time I’m at a desk using an external keyboard and trackpad.
But I was disapppointed how modest the performance gains (if any) were.
Unfortunately, the new Mac hardware under the new Mac OS is not a compelling value proposition.
When the 2013 MBP is running Sierra, and the 2018 Macs are running Mohave:
Mini2018: 5:02, MBP2018: 6:07, MBP2013: 6:13
When the older 2013 Macbook is upgraded to Mohave, the 2018MBP is 17% faster than the 2013 MBP. (But no escape key.)
So apples-to-apples-to-apples under Mohave, the Rspec runtimes are:
Mini2018: 5:02, MBP2018: 6:07, MBP2013: 7:20
Test setup: A suite of about 800 RSpec examples running in Docker Desktop v 184.108.40.206 for Mac… a web container with a Heroku-16 stack for a Rails 4.2.10 app with ruby 2.4.5, and a database container with Postgres 10.5. Tests were run 3 times on each platform and the times averaged. (Docker preferences set to 2 cores, 4GB RAM, 1 GB swap)
Verdict: the Mac Mini and the 2018 MBP both go back to the Apple Store tomorrow within Apple’s generous 14 day return window.
Fortunately, while I do need an 1TB internal SSD drive for the 2013 MBP, Apple did not completely future-proof the 2013 MBP and the internal SSD can be replaced.