FEX on Apple Silicon.
A native macOS x86-64 translation layer — no Rosetta, no virtual machine, no Windows licence.
Apple is retiring Rosetta, the piece of macOS that lets Intel code run on Apple Silicon. Almost every "Windows games on a Mac" setup quietly depends on it. When it goes, those setups stop working.
Ferrum is the replacement path. It translates x86-64 Windows code to ARM64 directly, sits underneath Wine for the Windows API, and hands graphics to DXVK → MoltenVK → Metal. Your games keep working, on hardware that never had an Intel chip in it.
Ferrum is Latin for iron, whose symbol is Fe. Add the subscript x and you get FEX, the translation layer underneath. In a chemical formula that subscript counts atoms, so Feₓ reads as an unspecified quantity of iron — which is about right for something that translates an unknown amount of somebody else's code.
Iron carries 26 protons — and Proton is the Wine-and-DXVK stack that made the Steam Deck work, same job on a different architecture. Element 26, built in 2026, shipping in Bourbon 26.
This corner of software also runs on drinks — Wine, Whisky, Bourbon. Ferrum has one hiding in it too.
| Windows programs run |  |
99% |
| DirectX 11 |  |
97% |
| Vulkan graphics bridge |  |
92% |
| Game windows and input |  |
90% |
| Speed |  |
90% |
| Drawing to the screen |  |
88% |
| Controllers |  |
80% |
| Sound |  |
78% |
| 2-D drawing (menus, HUD) |  |
74% |
| 32-bit games |  |
55% |
| Installers and saves |  |
52% |
| Shader stutter |  |
40% |
| Cutscene video |  |
35% |
| Older DirectX versions |  |
35% |
| DirectX 12 |  |
15% |
Every row links to what earned that number — in plain English, no code. Orange is the critical path to a game running. 822 automated checks pass; each one fails if its capability is removed.
Real DXVK runs on this port and creates an ID3D11Device at feature level 11_0.
A GPU-rendered frame reaches a real macOS window through a genuine
VK_KHR_swapchain. Audio plays through CoreAudio. Translated code costs about
3.2× native on the CPU — comfortable headroom inside a 60 fps frame.
Not done: a full game has not been driven end to end yet.
Ferrum's source is closed. This repository carries releases and documentation only — no source code. Development happens in a private repository.
- How it works — the four translations, in plain English
- Questions people actually ask — will my games work, do I need Windows, is it legal, how fast is it
- Progress in detail — what earned each number on the chart
- Roadmap — what stands up, what doesn't, what's next
Ferrum is the engine. Bourbon is the app it ships in — a native macOS front end that installs and drives the whole Windows-gaming stack so you don't have to.
- 🥃 Bourbon 26 on itch.io — the app itself
- 📦 Bourbon-OSS — open-source compatibility data, the DXVK patch, the Steam CEF shim, probes and community refresh tools
| FEX-Emu | x86/x86-64 → ARM64 translation (MIT) |
| Wine | the Windows API (LGPL) |
| DXVK | Direct3D → Vulkan |
| MoltenVK | Vulkan → Metal |
Ferrum is proprietary, closed-source software. The macOS port is not open
source, and nothing in this repository grants an open-source license to it. See
LICENSE.
You can license it two ways:
- As part of Bourbon 26 — end users get Ferrum as an integrated component under Bourbon's own terms. Nothing extra to sign.
- Commercially — for use outside Bourbon, redistribution, embedding, or source access. Reach out at contact@mikethetech.com.
The code this is built on keeps its own licenses and always will: FEX-Emu stays MIT for everyone (© 2019 Ryan Houdek and contributors), Wine stays LGPL and is loaded at runtime rather than modified, DXVK is zlib and MoltenVK is Apache-2.0. Upstream remains FEX-Emu/FEX and is never pushed to.
