Selects DX11 as the RHI. Ignored by builds without a DX11 path.
Display
UniversalAdded Jun 27, 2026Last checked Sep 9, 2026
Safe
-highCopy
Run the game at High process priority (Source engine games)
Effect
Raises the OS scheduling priority of the game process. It does not add CPU capacity, so it helps only where something else is competing for the processor.
Performance
UniversalAdded Jun 27, 2026Last checked Sep 9, 2026
Safe
-dx12Copy
Use the DirectX 12 renderer (Unreal Engine games)
Effect
Selects DX12 as the RHI. Ignored by builds without a DX12 path.
Display
UniversalAdded Jun 27, 2026Last checked Sep 9, 2026
Safe
-threads 4Copy
Set the size of the engine thread pool (Source engine games)
Effect
Takes a thread count; the default is 3. Setting it above the number of cores available does not help.
Performance
UniversalAdded Jun 27, 2026Last checked Sep 9, 2026
Safe
gamemoderun %command%Copy
Run the game under Feral GameMode (Linux)
Effect
Applies temporary host optimisations (CPU governor, I/O and process priority) for the game's lifetime, then restores them on exit. GameMode runs the game, so %command% is what it runs.
Proton-Deck
Feral GameModeAdded Jun 29, 2026Last checked Sep 12, 2026
Safe
PROTON_USE_WINED3D=1 %command%Copy
Use wined3d (OpenGL) instead of DXVK (Linux, Proton)
Effect
Routes d3d11, d3d10 and d3d9 through OpenGL-based wined3d rather than Vulkan-based DXVK. Usually slower; a fallback where DXVK fails.
On the General tab, find the Launch Options field.
Type or paste the option (e.g. -windowed) into the field. To use several at once, separate them with spaces (e.g. -windowed -novid).
Close Properties. Steam saves automatically, and the option applies next time you launch the game.
To remove one, reopen the same field and delete the text. Options are game-specific; an option that helps one game may do nothing (or misbehave) in another.
Worth knowing: a launch option can break a game's rendering, reset local settings, or trip anti-cheat in multiplayer. Read the description first, add one at a time, and treat anything rated above Safe as a deliberate experiment.
