CPAN.pm is not the fastest, no, though it generally spends most of its time running each distribution's tests before installing it, which while it does have a certain "start the install and go for lunch" to it is an excellent canary for if something's changed underneath you *before* you end up having to go spelunking your own code.

App::cpanminus (cpanm) is noticeably lighter, App::cpm (cpm) does parallel builds and skips tests by default.

An approach I've become quite fond of is using cpm to install fast into the local::lib I'm actually going to use, then creating a scratch setup in /home/tmp or similar and running cpanm in that under tmux/abduco/etc. to do a second install that *does* run the tests so I have those results to refer to later but don't have to wait for them right now.

(if I ever write a cpan client of my own, it's going to have a mode where it does a cpm-like install process and then backgrounds a test running process that logs somewhere well known so this approach becomes a single command, but I keep getting distracted by other projects ;)