Valve Expands SteamOS Compatibility Beyond Proton

Valve is expanding the compatibility options for its SteamOS operating system, aiming to increase the number of Windows games playable on its hardware. Beyond the well-known Proton layer, the company is now integrating FEX and a version of Rosetta 2 into its Steam architecture.

FEX is Valve's adaptation of an open-source project designed to emulate x86 processor instructions on ARM chipsets, such as those used in handheld devices like the Steam Deck. The emulator supports modern x86 instruction sets and utilizes graphics libraries like OpenGL and Vulkan to minimize overhead. It also employs code caching to reduce performance stuttering, according to Valve's developer documentation.

Valve has been supporting the lead developer of FEX since the project's early stages, anticipating the need for robust emulation technology for its gaming platform. This effort aims to bridge the gap for games not natively supported on Linux-based operating systems.

While Proton has been the primary tool for running Windows games on SteamOS, these new layers represent a further investment in cross-platform gaming capabilities, potentially broadening the library of titles accessible to Steam users on Linux.