The big picture: Proton is essential to the Steam Deck's ability to run thousands of PC games exclusively developed for Windows, and Valve hasn't stopped working to expand the range of its Linux compatibility layer. A major new update enables support for some important titles with the improvements permeating across all Linux systems.
Proton 9.0 is now available on Valve's GitHub repository. Steam users can also find it by searching their libraries, where several legacy versions should appear. Its numerous changes should improve support for around two dozen Windows games on the Steam Deck and other Linux devices. Many other titles have also received important bug fixes.
The Finals is one of the most popular games that becomes playable with the 9.0 stable release. The free-to-play competitive shooter from Embark Studios is one of the 100 most-played games on Steam. Thus, many users might benefit from the update.
Other relatively recent releases that Proton now supports include The Lord of the Rings: Gollum, Witch on the Holy Night, Sonic Colors: Ultimate, and Dinogen Online. However, two of the biggest highlights are the real-time strategy classics Command & Conquer: Red Alert 2, Tiberian Sun, and their expansion packs.
Moreover, Proton can now run some older titles that struggled on CPUs with high core counts by limiting the number of cores the games can see. These include Far Cry 2, Far Cry 4, The Witcher 2, Outcast – Second Contact, Prototype, and a few Warhammer 40K games.
Many other titles also received bug fixes including Civilization V, Immortals Fenyx Rising, Biomutant, Microsoft Flight Simulator, Super Robot Wars 30, Doom Eternal, Lethal Company, Lords of the Fallen, Sea of Thieves, Final Fantasy XIV, and Escape from Monkey Island.
Proton 9.0 also enables nvapi by default for most games, improving performance on Linux systems using Nvidia GPUs.
The new improvements ultimately stem from Wine 9.0, which became available in January. The Windows-to-Unix-like compatibility layer is the main tool Proton uses to run Windows games on SteamOS.
One of the January update's biggest changes improves how Wine handles 32-bit Windows applications, allowing them to run on purely 64-bit Unix-like operating systems like recent macOS versions that removed 32-bit support. Wine 9.0 also enhances Direct3D and Vulkan support while changing features in numerous other areas.