Heroku enforces a 512 MB memory limit (or 1024 MB on the 2X dynos), so that limits the practical number of processes running in the same dyno... especially if t

Heroku enforces a 512 MB memory limit (or 1024 MB on the 2X dynos), so that limits the practical number of processes running in the same dyno... especially if those are (heavy) full-stack web applications. Additionally, processes share the same CPU, so you'll not get the same performance as two processes in their own dynos. See https://devcenter.heroku.com/articles/process-model https://devcenter.heroku.com/articles/process-model and https://devcenter.heroku.com/articles/rails-unicorn https://devcenter.heroku.com/articles/rails-unicorn. Unicorn forks multiple OS processes within each dyno to allow a Rails app to support multiple concurrent requests. Generally no more than 3-4 processes will fit in one dyno.