Your GitHub Actions cache is the real bottleneck
Namespace, Avrea, and Blacksmith are among the fastest GitHub Actions runner providers on the market right now. According to Avrea's August 2026 benchmarks, they all score within about 1% of each other on raw CPU. The same benchmark shows warm builds (populated cache) beating GitHub's default cold start (cache disabled) by anywhere from 5x to more than 140x, depending on the project.