If you use mu4e in #Emacs for email, the 1.8 release is significant faster. (mu4e headers now render at least three times faster; and there is now sexp caching which improves performance with message searches as well.)

see https://github.com/djcb/mu/blob/master/NEWS.org

It's available in #Arch's AUR already.

(Still waiting for the #Guix package to update.... )