What Is Proton? How Linux Runs Windows Games Explained

The reason a Steam Deck can play thousands of Windows games without running Windows comes down to one piece of Valve software. Proton is a compatibility layer that translates Windows games so they run on Linux, and it does the job so well that roughly nine in ten Steam titles work through it. It is not an emulator and it is not a virtual machine. It is a clever translator sitting between a Windows game and a Linux system.

Quick Answer

Proton is Valve's compatibility layer, built on Wine, that lets Windows games run on Linux. It bundles Wine with DXVK and VKD3D to convert DirectX graphics calls into Vulkan, and around 90 percent of Steam games run through it. It ships inside Steam, so most of the time you just press play.

How Proton Works

Proton starts with Wine, a long-standing open-source project that lets Windows programs run on Linux by translating the calls a game makes to the operating system into calls Linux understands. Wine alone handles a lot, but games are demanding, especially their graphics, so Valve added more.

On top of Wine, Proton layers DXVK and VKD3D. These take the DirectX graphics commands that Windows games rely on and translate them into Vulkan, the modern graphics API that Linux speaks natively. DXVK covers the older DirectX versions, while VKD3D handles DirectX 12, the API behind most recent big releases. The result is that a game thinks it is talking to Windows and a graphics card on Windows, while underneath, Linux quietly does the work.

Why It Is Not an Emulator

This distinction matters for performance. An emulator pretends to be entire hardware, which is slow because every instruction has to be imitated. Proton translates instead. It passes the game's requests through to your real processor and graphics card, only converting the parts that speak Windows-specific languages like DirectX.

Because the heavy lifting still runs on your actual hardware, well-supported games often run at close to native speed, and in some cases the Vulkan translation even runs faster than the original DirectX path on Windows. That is why Linux handheld gaming feels genuinely viable rather than a compromise.

How to Turn It On

Proton is built into Steam, so for most games there is nothing to do. Valve marks many titles as verified, and those simply launch. For games not officially enabled, you switch on Steam Play in the settings, choose a Proton version, and Steam handles the rest. On a Steam Deck this is the default behaviour out of the box, which is why it plays so much of the catalogue without setup. If you are weighing up a Linux handheld, the handheld gaming console range gives a sense of what runs Proton natively today.

Frequently Asked Questions

Is Proton the same as Wine?

Not quite. Proton is built on Wine but adds extra components Valve maintains, including DXVK and VKD3D for graphics and several patches that improve game compatibility and performance beyond what plain Wine offers.

Do all Steam games work with Proton?

Most do, around 90 percent, but not all. Some games fail because of anti-cheat systems or specific dependencies. The community site ProtonDB tracks how well individual titles run before you buy.

Does Proton slow games down?

Usually very little, because it translates rather than emulates and still runs on your real hardware. Many games perform close to their Windows speed, and a few even run faster through the Vulkan translation.

Do I need to install Proton separately?

No. It ships inside Steam. You may need to enable Steam Play for unverified titles and pick a Proton version, but the software itself is already there.

Why does Proton convert DirectX to Vulkan?

Because Linux does not run DirectX natively, but it does run Vulkan. DXVK and VKD3D translate the DirectX calls games make into Vulkan, letting Windows games render properly on a Linux machine.