Following up with @JanVladimirMostert get a Chip or Raspberry or stuff if you're doing database development. It's easier to find bottlenecks when your server chokes compared to having a full blown fast machine which you might not always have in production. But it highly depends what kind of software you're building. Like @IvanBernatovic i'd say enough RAM (16GB+ if you use virtual machines) and a decent enough CPU to keep your IDE in the air. And those can consume quite a bit of both, depending on how many features you use. (don't start the holy war on me folks; notepad doesn't require much as well ;) )