Somebody Got Real SteamOS Running on a Mac, and Windows Games Are Hitting 200 FPS

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Valve’s real SteamOS is now running on Apple Silicon Macs. An independent, open-source project called FX Steam Launcher (its GitHub repo is fxgl/steamac) runs the official ARM64 SteamOS image Valve made for Steam Frame inside a virtual machine on macOS, according to VideoCardz. That means the full Steam Gaming Mode interface and Windows games running through Proton, on a Mac, while macOS keeps running alongside it. This is a community project, not something from Valve or Apple.

Somebody Got Real SteamOS Running on a Mac, and Windows Games Are Hitting 200 FPS

What you need to know

• What it is: a launcher that runs SteamOS in a virtual machine using Apple’s Hypervisor.framework and libkrun. It is not a native install, so macOS stays on the machine.
• Which SteamOS: Valve’s official ARM64 SteamOS, the one developed for Steam Frame. The launcher downloads the SteamOS image straight from Valve and supports SteamOS updates.
• What you get: SteamOS Gaming Mode, the KDE Plasma desktop mode, controllers, audio and GPU acceleration, in a window or fullscreen.
• Controllers: Xbox and other controllers work, plus mouse and keyboard.
• Who can run it: Apple Silicon Macs on macOS 15 or newer. The GitHub page lists about 150 GB of free space for the disk image (it’s a sparse image, so it only uses what it needs).
• How much memory: tester ETA Prime recommends at least 24GB of RAM for demanding games. Lighter games can work on 16GB.
• Status: still in active development. Version 1.9.8, released Nov 2, fixed compatibility with the SteamOS 0.6.0 preview after a Valve update stopped the virtual GPU from starting.

How it works

Getting a Windows game onto a Mac this way takes a stack of translation layers, per VideoCardz:

• Proton 11 for ARM64 runs the Windows game.
• FEX translates x86 instructions to ARM64, since Apple chips are ARM.
• DXVK handles DirectX 9, 10 and 11 games. vkd3d-proton handles DirectX 12.
• Mesa Venus plus either MoltenVK or KosmicKrisp carries the graphics to Apple’s Metal.
• Experimental DXMT lets DirectX 10 and 11 games talk to Metal directly, skipping the Vulkan step.

The fine print on DirectX 12: KosmicKrisp needs macOS 26 or later and supports DirectX 12 feature level 12_0. Games that need feature level 12_1 or Shader Model 6.6 don’t work yet. The launcher also lets you set how much CPU and memory the VM gets and shows MetalHUD performance stats.

The test results

YouTuber ETA Prime tested it on a MacBook Pro with an M4 Max (14-core CPU, 32-core GPU, 36GB of unified memory), with about 19GB given to the VM. Here’s what VideoCardz reported from that test:

• Stellar Blade: 800p, High, 70+ FPS
• The Witcher 3 (original version): 1080p, High, 70+ FPS
• Left 4 Dead 2: 1080p, High, 200+ FPS
• Fallout 4: 1080p, Medium, 60 FPS (capped)
• Red Dead Redemption: 1080p, Medium, 70+ FPS with drops into the 40s
• Grand Theft Auto IV: 1080p, Medium, 100+ FPS
• Skyrim: 1080p, High, 60 FPS
• Marvel vs. Capcom: Infinite: 1080p, Medium, playable with shader stutter

It’s not all clean. The Witcher 3 showed trees rendering wrong, and several games stuttered while compiling shaders. DOOM Eternal launched but wouldn’t run because it detected an unsupported GPU. Marvel’s Spider-Man: Miles Morales and Ghost of Tsushima didn’t start at all.

ETA Prime also tried an M6 Mac mini with 16GB of RAM. It ran Left 4 Dead 2 at over 140 FPS but struggled with heavier games because of memory swapping. On the M4 Max, giving the VM more than the chip’s eight performance cores actually lowered performance in some tests.

Reader poll

SteamOS runs on a Mac now. Would you game on it?

Vote and see what other Xbox fans think.

SteamOS runs on a Mac now. Would you game on it?

Yes, my MacBook is getting SteamMaybe, once DX12 games workNah, my gaming PC handles thisI'll stay on Xbox, thanks

Vote

Like having a say? Get OnPoint Weekly or argue it out on Discord.

OnPoint’s take: Here’s what people aren’t seeing in the “Steam on Mac” headlines: this only works because Valve built an ARM version of SteamOS for Steam Frame. Valve’s push to get Steam and Proton running on ARM chips is quietly turning into “your Steam library runs on more stuff,” and modders just proved it on hardware Valve never targeted. That’s huge for PC gaming as a platform. Your games follow you, not the box.

Look at that list, too. Fallout 4 and Skyrim, two Bethesda games, running on a MacBook through SteamOS. Xbox already plays nice with PC through Play Anywhere and Steam releases, and this is one more sign that the PC library is becoming the thing that matters most, wherever you play it. And yes, your Xbox controller works on it.

Real talk, though: this is a weekend project for tinkerers, not a Mac gaming fix. It’s stacked on a lot of translation layers, DX12 support is limited, some big games won’t boot, and you need a lot of RAM and storage. If you want the smooth version of this, a gaming PC or a handheld is still the move. But if you’ve got a beefy MacBook Pro sitting there, Steam just got a lot more interesting on it, no thanks to Apple.

Illustration: OnPoint 4 Gamers

Sources

• VideoCardz: Modders bring full SteamOS to Apple Macs, Windows games already playable (Nov 2, 2026)
• GitHub: fxgl/steamac, Valve’s ARM64 SteamOS in a VM on Apple Silicon
• ETA Prime on YouTube: SteamOS on a Mac?! This Actually Works!
• Dirty Static: SteamOS on Your Mac: steamac Runs Valve’s Official Build in a Tiny VM
• X: VideoCardz post