sounds like another hydra ( https://github.com/ngauthier/hydra ). It distributes your tests across processor cores, and optionally remote workers (other machines)
Why is Buffet better? (I'm genuinely interested)
Why is Buffet better? (I'm genuinely interested)
Alternatively, you have parallel_tests ( https://github.com/grosser/parallel_tests ) which can run on multiple cores. That's great if you use a mac pro, or some behemoth machine.
Little known there's testbot ( https://github.com/joakimk/testbot ) which can run tests across machines & cores. They've even worked in a bootstrapping process https://github.com/joakimk/testbot_cloud
From ( https://github.com/joakimk/testbot/wiki/How-testbot-is-used ) "... 60 minutes of tests to run in 10 minutes using 16 medium EC2 instances (32 cores), read the blog post." reports thoughtbot!
Code softly hackers.