The games do not have to be downloaded. You log in to Steam or Uplay (other providers are also supported) on the Shield, for example, then the game is streamed (platform called geforce now). Works tiptop. Nvidia has a decent server farm that can handle 4K with 60 FPS and the highest details. I don't notice any lag either. You can play with mouse and keyboard or with the controller. Many games are supported (
https://www.nvidia.com/de-de...). You just need a fast internet connection. Alternatively, you can stream the games from your PC to the shield. I'm extremely satisfied with it as an occasional gamer, and I practically don't need my desktop for gaming any more.