Pretty common if you run a lot of builds, have a big test suite or pay per minute. In my environment unpacking a 200MB .tar.gz containing node_modules from pre

Pretty common if you run a lot of builds, have a big test suite or pay per minute. In my environment unpacking a 200MB .tar.gz containing node_modules from previous runs takes half the time on RAM disk vs. SSD local storage. Python doesn't gain as much, packages tend to have fewer small files but there still is a small gain. How much tests benefit from using a RAM disk depends heavily on what they do, I have seen 10% for React apps. We also use other simple tricks like running databases with disabled fsync, mv instead of rm, cache whatever can be cached between CI runs, shallow checkouts and so on. Nothing ground breaking but it all adds up. However, for pipelines which run for five minutes twice a day I don't even bother.