Hi NGU , here's a list of all available command lines for GTA V PC
Commandline parameters can be added to the "commandline.txt" file in the root of the game folder. If this file doesn't exist, you can create a new text document and copy it in the game install directory. Rename this file to "commandline".
-UseAutoSettings Use automatic generated settings
-benchmark Starts the benchmark test from the command line
-benchmarkFrameTimes Optionally output the individual frame times from the benchmark
-benchmarkIterations Specifies the number of iterations to run the benchmark for
-benchmarkPass Specifies an individual benchmark scene test should be done, and which test that should be
-benchmarknoaudio Disable audio processing for graphics benchmark purposes
-disableHyperthreading Don't count hyperthreaded cores as real ones to create tasks on
-goStraightToMP Jump straight to MP while loading
-ignoreDifferentVideoCard Don't reset settings with a new card
-ignoreprofile Ignore the current profile settings
-mouseexclusive Game uses mouse exclusively.
-noInGameDOF Disable In-game DOF effects
-safemode Start settings at minimum but don't save it
-shadowSoftness Selects between linear, rpdb, box 4x4, soft 16
-uilanguage Set language game uses
-useMinimumSettings Reset settings to the minimum
-HDStreamingInFlight Enable HD streaming while in flight
-SSA Enable SSA
-SSAO Set SSAO quality (0-2)
-anisotropicQualityLevel Set anisotropic Filter Quality Level (0-16)
-cityDensity Control city density (0.0 - 1.0)
-fogVolumes Enable lights volumetric effects in foggy weather
-fxaa Set FXAA quality (0-3)
-grassQuality Set grass quality (0-5)
-lodScale Set LOD Distance Level (0.0-1.0f)
-particleQuality Set particle quality (0-2)
-particleShadows Enable particle shadows
-pedLodBias Set Pedestrians LOD Distance Bias (0.0-1.0f)
-postFX Set postFX quality (0-3)
-reflectionBlur Enable reflection map blur
-reflectionQuality Set reflection quality (0-3)
-shaderQuality Set shader quality (0-2)
-shadowLongShadows Enable shadow rendering for dusk and dawn
-shadowQuality Set shadow quality (0-3)
-tessellation Set tessellation on or off (0-3)
-textureQuality Set texture quality (0-2)
-txaa Enable NVidia TXAA
-vehicleLodBias Set Vehicles LOD Distance Bias (0.0-1.0f)
-waterQuality Set water quality (0-1)
-keyboardLocal Sets the keyboard layout to the specified region.
-hdr Set the whole rendering pipeline to 16-bit
-noquattransform Don't use quaternion transforms for placed entities
-DX10 Force 10.0 feature set
-DX10_1 Force 10.1 feature set
-DX11 Force 11.0 feature set
-GPUCount Manual override GPU Count
-adapter Use the specified screen adapter number (zero-based)
-borderless Set main window to be borderless
-disallowResizeWindow Do Not allow the window to be resized
-frameLimit Number of vertical synchronizations to limit game to
-fullscreen Force fullscreen mode
-height Set height of main render window (default is 480)
-multiSample Number of multisamples (1, 2, 4, 8, or 16)
-width Set width of main render window (default is 640)
-windowed Force windowed mode
-StraightIntoFreemode If present the game will automatically launch into the multiplayer game in freemode.