Modders Unlock 32-Bit Legacy PC Gaming On Apple Silicon With SteamOS

As powerful as modern Apple Silicon-powered Macs have become for modern gaming workloads, Mac gamers everywhere remember that sinking feeling when they first received the notification that their favorite 32-bit Steam games would no longer work on new Macs. Thanks to the hard work of Valve and the open source community, though, the ARM-based SteamOS is more than capable of filling that compatibility gap, and modders have done the work to create a seamless SteamOS port for Apple Silicon.

This SteamOS port for Apple Silicon is officially called "FX Steam Launcher" (steamac on GitHub) and it runs within "a lightweight VM on Apple Silicon" with libkrun, Venus, MoltenVK, CoreAudio, and controller support. For more modern games, the results can be a little mixed, and I generally wouldn't recommend using steamac for modern games just yet.

Benchmarking with a 2024 MacBook Pro powered by an M4 Max SoC, tech-focused YouTuber ETA PRIME revealed that certain modern games like Stellar Blade were indeed playable above an average 60 FPS. However, upscaling from a low 800p internal resolution was required.


Other modern games, like Doom Eternal or Spider-Man: Miles Morales simply refused to run on the cobbled-together configuration at all. If you're focused solely on modern AAA games, there's minimal value in the FX Steam Launcher for you, since official Mac (or compatibility layer) support for those releases is in a much better state; you can simply play them directly on your machine.

The big utility here is actually the FX Steam Launcher's ability to re-enable 32-bit gaming on modern Macs. Left 4 Dead 2, easily one of the most popular 32-bit games still played on Steam, runs at an average of 200 FPS through steamac. While the overhead (and graphical glitches) for modern games like Stellar Blade is certainly noticeable, these issues are greatly diminished for 32-bit games, and the trade-off is that they're actually playable again.


All told, it's great work from the open source community here, but especially the FX Steam Launcher team. The source code for the project is viewable on GitHub at the steamac repo, and an easy direct download is available on the official web page.