I can also vehemently endorse Andrea Corallo's work on native-comp/libgccjit. The compilation can be finicky so I recommend looking at the AUR script here: https://aur.archlinux.org/cgit/aur.git/tree/PKGBUILD?h=emacs... or this lovely article: https://www.masteringemacs.org/article/speed-up-emacs-libjan...

Also, for those of you who didn't know what GCMH was:

https://github.com/emacsmirror/gcmh

> GCMH - the Garbage Collector Magic Hack

> Enforce a sneaky Garbage Collection strategy to minimize GC interference with user activity. During normal use a high GC threshold is set. When idling GC is triggered and a low threshold is set.