so one day i was chilling on the beamng website and I was going threw the mods and selecting the view in game button and the game started up with out steam running (yes i know i could have bought it with out steam but that's where i saw it for the first time and got it) but like i was saying without steam running in the background the game ran like17ish% better just saying this for the ones that don't have a NASA computer
less ram and cpu. the Steam client itself runs on Chromium, so its essentially an extremely glorified web browser. so while you can launch games without steam running, some games (like Portal 2) will throw a fit because you don't have steam running
prob bump and an quick correction; it actually just runs without steam overlay (and doesn't change performance, just feels like it did, but results may vary from pc to pc so it can be true)