You should really only need one process per core, plus a few thread per process. Obviously, this is a problem on Heroku where they give you 8 "cores" but only 5

You should really only need one process per core, plus a few thread per process. Obviously, this is a problem on Heroku where they give you 8 "cores" but only 512mb of RAM per 1x dyno but on a DigitalOcean or AWS server you shouldn't be running out of RAM before maxing all cores.