The details you listed sound accurate for the built-in GitHub-hosted runners. GHA also supports bringing your own self-hosted runners [1][2] where you install

The details you listed sound accurate for the built-in GitHub-hosted runners. GHA also supports bringing your own self-hosted runners [1][2] where you install their agent, so you could, e.g., use an ARM instance on AWS with tons of cores. It looks like CircleCI offers this as well. [1]: https://docs.github.com/en/actions/hosting-your-own-runners/about-self-hosted-runners https://docs.github.com/en/actions/hosting-your-own-runners/... [2]: https://github.com/actions/runner https://github.com/actions/runner