"Does not work"

After enabling the module no result is seen.

It should be documented why this can be the case.

First, there is a variable without UI in the source: "panels_why_so_slow?" (yes, it has a question mark).

To enable use
drush vset panels_why_so_slow? 1
(or delete it, it defaults to true).

The other possible reason is trickier, i had to debug this once:
The panels render pipeline setting may be overrideen so the module's default-altering has no effect.

Cure this by deleting the DB entiries (i don't think there is a UI for that):
drush sqlq "DELETE FROM `panels_renderer_pipeline`;"