Valve's FEX translation layer enables x86 PC gaming on ARM-based SteamOS headsets

Valve has released FEX, a translation layer that allows ARM-based VR headsets to run x86 PC games from the Steam library without requiring a connected PC. FEX functions by translating x86 instructions into ARM-native code, a process that complements existing compatibility layers like Proton and GameScope. While previous methods relied on single-translator emulation that often resulted in poor performance, FEX optimizes this process by rewriting x86 code into ARM-native versions, which can then be cached to improve startup times and reduce stuttering. Valve has integrated FEX directly into Proton, allowing the translation to occur when a Windows application makes calls to Windows APIs. Although this approach significantly improves performance, it still incurs a 10-20% CPU performance penalty compared to native execution. The Steam Frame, which utilizes a Snapdragon 8 Gen 3 chip, serves as the primary demonstration of this technology. Valve intends for SteamOS to eventually run on any capable gaming platform, including tablets and phones, by leveraging this open-source software stack.

Tech4K Staff8:07 watch

Valve has released FEX, a translation layer that allows ARM-based VR headsets to run x86 PC games from the Steam library without requiring a connected PC. FEX functions by translating x86 instructions into ARM-native code, a process that complements existing compatibility layers like Proton and GameScope. While previous methods relied on single-translator emulation that often resulted in poor performance, FEX optimizes this process by rewriting x86 code into ARM-native versions, which can then be cached to improve startup times and reduce stuttering. Valve has integrated FEX directly into Proton, allowing the translation to occur when a Windows application makes calls to Windows APIs. Although this approach significantly improves performance, it still incurs a 10-20% CPU performance penalty compared to native execution. The Steam Frame, which utilizes a Snapdragon 8 Gen 3 chip, serves as the primary demonstration of this technology. Valve intends for SteamOS to eventually run on any capable gaming platform, including tablets and phones, by leveraging this open-source software stack.

FEX is a new translation layer that enables ARM-based devices to run x86 PC games natively. The software works by translating x86 instructions into ARM-native code, which can be cached for better performance.

FEX is integrated into Proton, allowing it to handle Windows API calls during game execution. The technology incurs a 10-20% CPU performance penalty, which is comparable to the overhead of running Proton on the Steam Deck.

Valve aims to make SteamOS compatible with a wide range of ARM-based gaming hardware, including tablets and phones. The Steam Frame headset uses a Snapdragon 8 Gen 3 processor to run these translated PC games.

Chapter guide

Introduction to FEXAn overview of the FEX translation layer and its role in enabling standalone PC VR gaming on ARM hardware.x86 vs. ARM ArchitectureA technical explanation of the differences between x86 and ARM instruction sets and why translation is necessary.The Role of ProtonHow Proton and FEX work together to bridge the gap between Windows games and ARM-based Linux systems.How FEX WorksA detailed look at how FEX translates x86 code to ARM and the benefits of its experimental code cache.Performance CostsA discussion on the performance trade-offs and the 10-20% CPU overhead associated with translation.Lepton and Android CompatibilityAn introduction to Lepton, a compatibility layer for running Android-based VR games on the Steam Frame.Future of SteamOSValve's long-term vision for SteamOS running on various ARM-based gaming platforms.

Worth noting

  • The video is sponsored by Proton Drive, which is promoted as a privacy-focused file storage service.
  • Performance metrics are based on internal testing and may vary depending on the specific game and hardware configuration.
  • The long-term viability of running SteamOS on non-Valve hardware remains subject to community development and developer support.

Watch the original video ↗