What factors would make app restarts slow on one machine but fast on another (same app)?

I have a large Meteor app, and when I make a change to it, it takes ~5 seconds to restart and then reload in the browser. When another developer makes the same change to the same codebase, it takes ~40-60 seconds to restart and reload in the browser.

Same app, same browser, same Meteor version (reinstalled), both iMacs with similar specs. Internet speed is fast in both cases.

Does anyone know what the most likely causes of this are? Available memory seems obvious, but he has the same issue when all other apps are shut down. Are there system settings that could impact this so dramatically?