Quite simply: No frameworks. Some games nowadays are built using Electron, which means they include a full web browser which will then run the game logic in Ja

Quite simply: No frameworks. Some games nowadays are built using Electron, which means they include a full web browser which will then run the game logic in JavaScript. That alone can cause +1000% CPU usage. Unity (e.g. RimWorld) wastes quite a lot of CPU cycles on things that you'll probably never use or need, but since it's a one-size-fits-all solution, they need to include everything. For Unreal Engine, advanced studios will actually configure compile-time flags to remove features that they don't need, and it's C++ and in general well designed, so that one can become quite efficient if you use it correctly. And then there's script marketplaces. They will save you a lot of time getting your game ready for release quickly, but they are usually coded by motivated amateurs and super inefficient. But if CPUs are generally fast enough and the budgets for game developers are generally low, many people will trade lower release performance for a faster time to market. => Modern games are slow because it's cheaper and more convenient that way. But there still are tech demos where people push efficiency to the limit. pouet.net comes to mind. And of course the UE5 demo which runs on an AMD GPU and a 8-core AMD CPU: https://www.youtube.com/watch?v=iIDzZJpDlpA https://www.youtube.com/watch?v=iIDzZJpDlpA