SteamOS
Valve's Linux-based, console-like handheld OS built around Steam and Proton, optimized for battery and simplicity.
SteamOS is a Linux distribution built by Valve specifically for the Steam Deck and, more recently, licensed to third-party handhelds like the Lenovo Legion Go S. It boots straight into a controller-friendly, console-style interface rather than a Windows desktop, and runs Windows games through the Proton compatibility layer.
Because it strips away background Windows services, telemetry and update churn, SteamOS handhelds typically get noticeably better battery life and more consistent frame pacing than the same hardware running Windows. The trade-off is that non-Steam storefronts and some anti-cheat-protected multiplayer games either need workarounds or do not work at all.
Why it matters when buying
Choose SteamOS if most of your library is on Steam and you value battery life, quick suspend/resume and a clean console-like UI over broad storefront support. It is the default choice for buyers who mainly play single-player or non-anti-cheat multiplayer games.
