Replied to https://www.sadlerjw.com/2018/09/20/sublime-merge/ by Jason Sadler (sadlerjw.com)

We have a custom implementation of Git for reading repositories, which drives a lot of our high performance functionality. However we defer to Git itself for operations that mutate the repository (Staging, Committing, Checking out branches, etc).

So yeah, Sublime Merge is really fast.
I don’t love the UI, but it’s early days yet.
Seriously, it’s so, so fast.