As detailed in bug#41077, I compiled the feature/native-comp branch[1]
on a low-end-ish laptop[2], blacklisting char-fold.el since native
compilation took too much memory for this file.

As reported there, I get appreciable speedups on the benchmarks
distributed in the elisp-benchmarks ELPA package, except for one
specific test: fibn.  When native-compiled (with any value of
comp-speed), this test makes Emacs abort with the message:

> Memory exhausted--use C-x s then exit and restart Emacs

I've plotted some graphs showing fibn's memory consumption for every
value of comp-speed, as well as for emacs master[3] (where all 3
iterations run to completion):