Fex-Emu – Run X86 Applications on Arm64 Linux Devices
Key topics
Regulars are buzzing about FEX-emu, an open-source emulator that lets you run x86 applications seamlessly on ARM64 Linux devices, potentially revolutionizing the way we use Linux on non-x86 architectures. As commenters dive into the project's implications, some highlight its potential to boost gaming on ARM devices, while others discuss the technical hurdles and trade-offs involved in emulation. The thread erupts into a lively debate about the future of cross-architecture compatibility, with some predicting a surge in adoption and others cautioning about potential performance bottlenecks. As the discussion unfolds, a consensus emerges that FEX-emu is an exciting development that could shake up the Linux ecosystem.
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- 01Story posted
Nov 12, 2025 at 3:15 PM EST
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Nov 12, 2025 at 3:15 PM EST
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Nov 20, 2025 at 11:30 PM EST
about 1 month ago
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> It supports forwarding API calls to host system libraries like OpenGL or Vulkan to reduce emulation overhead. An experimental code cache helps minimize in-game stuttering as much as possible. Furthermore, a per-app configuration system allows tweaking performance per game, e.g. by skipping costly memory model emulation. We also provide a user-friendly FEXConfig GUI to explore and change these settings.
> On the technical side, FEX features an advanced binary recompiler that supports all modern extensions of the x86(-64) instruction set, including AVX/AVX2. The heart of this recompiler is a custom IR that allows us to generate more optimized code than a traditional splatter JIT. A comprehensive system call translation layer takes care of differences between the emulated and host operating systems and implements even niche features like seccomp. A modular core enables FEX to be used as a WoW64/ARM64EC backend in Wine.
Used by the new Steam Frame (https://store.steampowered.com/sale/steamframe) which is an ARM64 Snapdragon 8 Gen 3 that will run PC and PCVR gaming titles.
I've tested it on an Ampere workstation, and was trying it on a Pi, but it seems with Trixie, there may be some bugs with both that and box64 right now, I was having trouble with both of them.
https://news.ycombinator.com/item?id=45903610#:~:text=Valve%...
FEX is the shootstring, extra special discount budget (not maligning) version of Rosetta. Apple should sell Rosetta to Valve.
The JavaScript instruction is cooler though.
https://developer.arm.com/documentation/dui0801/g/A64-Floati...
QEMU exists. I doubt they want the bad press of suing an Open Source project everyone is using.
Gabe Ownership/co-founder:
- Valve - Yacht Companies - Starfish Neuroscience (Neuralink) - Submarine Companies
https://interfacinglinux.com/2025/06/30/fex-emu-gaming-on-th...
https://fex-emu.com/FEX-2510/
FEX also has settings which weaken or disable TSO altogether, favoring performance over correctness. You wouldn't want to rely on those for anything important but a game possibly crashing isn't the end of the world.
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