This! We went from 20!! minutes and 1.2k monthly spend on very, very brittle action runs to a full CI run in 4 minutes, always passing, by just by going to Hetzner's server auction page and bid on a 100 euro Ryzen machine.
After self hosting our builds ended up so fast, that we were actually waiting for was GitHub scheduling our agents, rather than it being the job running. It sucked a bit, because we'd optimized it so much, but we on 90th percentile saw that it took 20-30 seconds for github to schedule the jobs as they should. Measured from when the commit hit the branch, to the webhook begin sent.
After self hosting our builds ended up so fast, that we were actually waiting for was GitHub scheduling our agents, rather than it being the job running. It sucked a bit, because we'd optimized it so much, but we on 90th percentile saw that it took 20-30 seconds for github to schedule the jobs as they should. Measured from when the commit hit the branch, to the webhook begin sent.