37 env vars · 5 unique to this variant · scraped 28 Jul 2026

NameTypeDescription
COPYPREFIX uniqueboolSet to 1 to enable. If -steamdeck is used on steam (or SteamDeck=1 is set), copies the game's prefix and shader cache from the game partition to the local steam steamapps folder. Logic is reversed if -steamdeck not enabled (or SteamDeck=0)
HOST_LC_ALL unknownSet value to a locale to override all other system locale settings for a game. This variable should be used instead of LC_ALL.
PROTON_DEBUG_DIR pathRoot directory for the Proton debug scripts, /tmp by default.
PROTON_DLSS_INDICATOR boolEnable the DLSS overlay at the bottom left portion of the screen. This is exactly the same as FSR4_WATERMARK=1
PROTON_DLSS_UPGRADE boolg).dll DLLs. Version to download can be specified by supplying it as a value, like so PROTON_DLSS_UPGRADE="310.2", instead of 1, to download version 310.2.1.0. This option also sets DXVK_NVAPI_DRS_SETTINGS` to use the latest preset. If you provide your own config for it through this environment variable, your configuration is going to be applied..
PROTON_DUMP_DEBUG_COMMANDS boolWhen running a game, Proton will write some useful debug scripts for that game into $PROTON_DEBUG_DIR/proton_$USER/.
PROTON_ENABLE_MEDIACONV boolEnable media converter for winegstreamer. This is not needed for winedmo, since the mediaconverter implementation of the codecs doesn't override the underlying implementation.
PROTON_ENABLE_NVAPI boolEnable NVIDIA's NVAPI GPU support library.
PROTON_FORCE_LARGE_ADDRESS_AWARE boolForce Wine to enable the LARGE_ADDRESS_AWARE flag for all executables.
PROTON_FSR3_UPGRADE uniquebool
PROTON_FSR4_INDICATOR boolEnable the FSR4 watermark at the top left portion of the screen.
PROTON_FSR4_RDNA3_UPGRADE uniqueboolIdentical to PROTON_FSR4_UPGRADE but for RDNA3 GPUs. Enables some required compatibility options and downloads version 4.0.0 of the DLL by default.
PROTON_FSR4_UPGRADE boolAutomatically download amdxcffx64.dll and upgrade games with FSR 3.1 to use FSR 4. Version to download can be specified by supplying it as a value, like so PROTON_FSR4_UPGRADE="4.0.1", instead of 1. Downloads version 4.0.2 of the required DLL by default. This option also disables AMD Anti-Lag 2 currently due to various issues.
PROTON_HEAP_DELAY_FREE boolDelay freeing some memory, to work around application use-after-free bugs.
PROTON_LOG boolConvenience method for dumping a useful debug log to $HOME/steam-$APPID.log. For more thorough logging, use user_settings.py.
PROTON_NO_D3D10 boolDisables DX10.
PROTON_NO_D3D11 boolDisables DX11.
PROTON_NO_D3D12 boolDisables DX12.
PROTON_NO_D3D9 boolDisables DX9.
PROTON_NO_ESYNC boolDo not use eventfd-based in-process synchronization primitives.
PROTON_NO_FSYNC boolDo not use futex-based in-process synchronization primitives. (Automatically disabled on systems with no FUTEX_WAIT_MULTIPLE support.)
PROTON_NO_NTSYNC boolDo not use the ntsync kernel module for in-process synchronization primitives.
PROTON_NO_WRITE_WATCH boolDisable support for memory write watches in ntdll. This should only be applied if you have verified that the game can operate without write watches. This can improves performance for some very specific games.
PROTON_OLD_GL_STRING boolSet some driver overrides to limit the length of the GL extension string, for old games that crash on very long extension strings.
PROTON_USE_SDL boolUses SDL input instead of HIDRAW/Steam Input.
PROTON_USE_SECCOMP boolEnable seccomp-bpf filter to emulate native syscalls, required for some DRM protections to work.
PROTON_USE_WAYLAND boolEnables the Wayland driver.
PROTON_USE_WINED3D boolUse OpenGL-based wined3d instead of Vulkan-based DXVK for d3d11 and d3d10. This used to be called PROTON_USE_WINED3D11, which is now an alias for this same option.
PROTON_USE_WOW64 uniqueboolEnables wow64.
PROTON_USE_XALIA boolEnable Xalia, a program that can add a gamepad UI for some keyboard/mouse interfaces, or set to 0 to disable. The default is to enable it dynamically based on window contents.
PROTON_XESS_UPGRADE bool
WAYLANDDRV_PRIMARY_MONITOR unknownSpecify primary monitor where the value is something like eDP-1. Requires the Wayland driver.
WAYLANDDRV_RAWINPUT uniqueboolA value of 0 disables unaccelerated input and uses accelerated input. Any positive real number (like 0.5) adjusts the sensitivity of rawinput. Requires the Wayland driver.
WINE_DO_NOT_CREATE_DXGI_DEVICE_MANAGER boolSet to 1 to enable. Required for video playback in some games to not be miscolored (usually tinted pink)
WINE_FULLSCREEN_FSR boolEnable AMD FidelityFX Super Resolution (FSR), use in conjunction with WINE_FULLSCREEN_FSR_STRENGTH. Only works in Vulkan games (DXVK and VKD3D-Proton included).
WINE_FULLSCREEN_FSR_CUSTOM_MODE unknownSet fake resolution of the screen. This can be useful in games that render in native resolution regardless of the selected resolution. Parameter WIDTHxHEIGHT
WINE_FULLSCREEN_FSR_STRENGTH unknownAMD FidelityFX Super Resolution (FSR) strength, the default sharpening of 5 is enough without needing modification, but can be changed with 0-5 if wanted. 0 is the maximum sharpness, higher values mean less sharpening. 2 is the AMD recommended default and is set by GE-Proton by default.
Proton Variants v0.4.1 | GitHub