So, ST3 is well written. The core C libs are fast and questionable plugin structure aside, it usually holds up well.
Atom is JS based, which is just plain slow to render.
emacs/Vim, awesome, but same issue:
When dealing with large JSON/text files none appear to have multi-threading support for complex operations (such as regex search/replace). I have an 8-core Xeon and am experiencing 2-5 minutes to render on these operations with only one core recruited.
Is there any editor that uses threads effectively to distribute operations on large files?
Most Regex engines are built upon Nondeterministic Finite Automata with additional features. Translating NFA's to a Deterministic Finite Automata can produce an exponential number of states and hence correspondingly long run times for certain regex's.
Throwing more cores at an NFA probably doesn't help much unless you are doing things like prefetch, predictive branching, and other operations analogous to modern CPU techniques. Even if there was a Regex engine that did those things exponential time divided by number_of_cores is still exponential time. And there would still be corner cases that gained no benefit.
The practical alternatives are:
1. Tuning the regex to better performance.
2. Using another search engine such as a DFA based Regex engine like egrep, flex, or an appropriate version of awk.
3. Storing the text files in a medium designed for efficient search...i.e. a database.
4. Accept the computer science behind convenient regex implementation isn't a free lunch.
To learn more about this XY problem check out Mastering Regular Expressions from O'Reilly.