Short answer
Run ARC if you already operate Kubernetes, want runners inside your own network and accept the operations work; use a managed service if you want to change one runs-on line and have someone else operate the runners. CI Bench v1 did not measure ARC itself. It measured self-hosted VM setups (Self-hosted runners on Google Cloud: 59% lower cost per job at 100,000 jobs a month, 59% lower at 1,000; RunsOn: 88% lower cost per job at 100,000 jobs a month, 43% higher at 1,000; Self-hosted runners on AWS (one VM per job): 62% lower cost per job at 100,000 jobs a month, 49% lower at 1,000) and managed services (Vitko Runners (warm starts + test splitting) 84% lower at 10,000; Vitko Runners 84% lower at 10,000; Blacksmith 52% lower at 10,000; Ubicloud 83% lower at 10,000), all against GitHub-hosted (ubuntu-latest); operations time is not in those costs. Maintained by Vitko, Inc., which sells one of the products measured.
What ARC is
GitHub documents ARC as "a Kubernetes operator that orchestrates and scales self-hosted runners for GitHub Actions": runner scale sets scale with the number of running workflows, and "controlled runners can be ephemeral and based on containers" (read 2026-10-27). You run the cluster, the controller, the runner images, upgrades and security hardening.
ARC compared with a managed service
| Topic | ARC on your Kubernetes | Managed runner service |
|---|---|---|
| Who operates it | You: cluster, controller, images, upgrades | The provider |
| Switching cost | Install the controller and scale sets; point runs-on at the scale set name | Change one runs-on label, then check the provider’s limits |
| Where jobs run | Your network and cloud account | The provider’s infrastructure (or your account, for bring-your-own-cloud options) |
| Cost shape | Your cloud bill plus fixed costs for the cluster; per-job cost falls as volume rises | Per-minute or per-second list price (list prices) |
| Isolation | Depends on your configuration; GitHub notes self-hosted runners have no clean-VM guarantee | Check the provider’s statement (questions to ask) |
What the benchmark measured
CI Bench v1 measured self-hosted VM setups on AWS and Google Cloud and managed services on the same 12 workloads, with all-in cost for self-hosted options (cloud bill plus fixed monthly costs spread over the volume). See self-hosted vs managed GitHub Actions runners, measured and the calculator. ARC was not one of the configurations.
More: 12 options compared · ranked by speed · ranked by cost per job · price per minute, 2 and 4 vCPU · self-hosted vs managed · alternatives to GitHub-hosted.
Method: how the runs were made; data: results.json; every raw record: the repository. Maintained by Vitko, Inc., which sells one of the products measured. Page dated October 27, 2026.