The following settings have the most significant impact on your framerate and should be lowered first if you are struggling with performance:

Found in Advanced Graphics, setting this to 0.500 or 0.667 lowers the internal render resolution while keeping the UI sharp, providing a major performance boost for weak GPUs.

Enable Game Mode and Hardware-Accelerated GPU Scheduling in Windows settings to prioritize the game's access to hardware resources.

Your PC's background environment often dictates how smoothly GTA 5 runs:

Set your power management mode to "Prefer Maximum Performance" and cap your global framerate to 3 FPS below your monitor's refresh rate (e.g., 141 FPS for a 144Hz screen) to prevent engine instability.