Yeah this is one reason, or Emacs freezing for up to a minute when updating packages. Also when using an LSP I notice latency.

I use Emacs GUI (outside of the terminal) and comparing performance for rending to something like Zed or Sublime is definitely noticeable. It’s great that Emacs is so resource efficient but sometimes I wish it used more of my beefy computer(s).

Like I said I still love Emacs and it’s okay for it to make a different set of trade-offs. I honestly didn’t think I’d ever switch editors but here we are!

Removing the interpreter lock for a few specialized tasks (without sweeping runtime changes to Emacs) would be enough to fix most of these issues -- parsing JSON from process output into lisp data in a background thread is one candidate. [1]

Installing packages does not need to block either, there is no architectural limitation here. The Elpaca package manager for Emacs provides async, parallel package updates. Loading packages into the Lisp image will block though, there's no way around that.

The other big source of input lag is garbage collection, and there are some ongoing efforts to use the MPS library in Emacs for a copying, concurrent GC. This is a big change and I don't know if this experiment will go anywhere, but Eli Zaretskii and co are trying.

[1]: https://github.com/emacs-lsp/emacs

That's fair I guess. In the case of IO that can be an issue. When I hear multicore, I assume we're talking about parallelism, not concurrency.

As for LSP, other than the Nim langserver, I've been quite satisfied with Eglot's performance. I'm curious what your setup is like. To be fair, I'm running a highly customized Doom Emacs config, so it's possible I inherited some non-vanilla optimizations I'm not aware of.