
(Click for general game info.)
System requirements:

Latest drivers: (as at 21/12/2017)
Nvidia: 388.71
AMD: 17.12.2
Intel: Depends on your processor; download the driver update utility
Tips and tricks:
Benchmarks (NV), settings comparisons, and recommended settings (NV): See Nvidia's tweak guide. (Credit to AndyBNV.)
Various CPU/GPU benchmarks and data: See this GameGPU article.
Note: The article is in Russian, but the data is presented via graphs.
Cap the framerate/potentially improve frametimes: Download RivaTuner Statistics Server, input your desired framerate limit in the "Framerate limit" box, and hit enter (the program comes bundled with MSI Afterburner and earlier versions of EVGA PrecisionX). Alternatively, those with an Nvidia GPU have the option of Nvidia Inspector, which can also be used to impose a framerate cap, either in a similar manner to RTSS or by way of forcing a different vsync interval (click the small tool icon to open the game profile section).
Note: Useful if you your system can't maintain, say, 60fps and you're sensitive to the wild fluctuations, or you're experiencing uneven frametimes. The greater window the engine has to render a given frame, if you're imposing a lower framerate than the game can otherwise provide, may also help in alleviating stuttering related to data streaming.
Stop the game from crashing after 15 minutes on touch-capable systems running Windows 10: Open the task manager, switch to the Services tab and disable TabletInputService.
Actually disable mouse acceleration/smoothing: Open My Documents\My Games\Far Cry 4\[account id string]\GamerProfile.xml and set MouseAccelerationOn, MouseAcceleration, Smoothness, Smoothness_Ironsight and UseMouseSmooth to 0. (Credit to jacksepticeye.) If you're still finding mouse movements to be a little off, follow this guide. (Credit to Cr1N @ Reddit via zXe.)
Mitigate stuttering (1): Open My Documents\My Games\Far Cry 4\[account id string]\GamerProfile.xml and set DisableLoadingMip0 to 1. (Credit to Gormenghast.)
Note: Affects the quality of some textures.
Mitigate stuttering (2): Open My Documents\My Games\Far Cry 4\[account id string]\GamerProfile.xml and set GPUMaxBufferedFrames to a higher value (1-3). (Credit to pixel monkey.)
Note: Will slightly increase VRAM usage.
Mitigate stuttering (3): Unpark all of your processor's cores as Windows may be erroneously leaving some in a reserved state. (Credit to ChristianTaliban.)
Note: Not applicable if you're running Win8 or higher.
Skip intro videos: Create a shortcut to the game's executable and add -skipintro to the target line. (Credit to Unain.)
Note (1): If you're playing the game through Steam (including via a non-Steam shortcut), you can instead add the parameter using the client itself by right-clicking the game, selecting "Properties" and then "Set launch properties".
Note (2): As of v1.4, the command no longer works with the Uplay version of the game. The Steam version remains unaffected.
(For those with SLI) Remove temporal image retention when using SMAA: Using Nvidia Inspector, replace the default Far Cry 4 SLI (DX1x) bits with those of Far Cry: Blood Dragon. (Credit to riflen.)
Note: If you're unfamiliar with Nvidia Inspector, here is a step-by-step guide.
Force anisotropic filtering: Using Nvidia Inspector, click the tool icon to open the driver profile section, navigate to the game's profile and change Anisotropic filtering mode to "User defined / off" and Anisotropic filtering setting to your desired level.
Note: AF is virtually "free" on modern GPUs, so in all likelihood you'll be able to use 16x without a noticeable impact on performance.

Graphics settings:
Graphics quality (presets): Low; Medium; High; Very High; Ultra; Nvidia (Ultra + soft shadows)
Motion blur: Off/On
Textures: Low; Medium; High; Very High; Ultra
Shadows: Low; Medium; High; Very High; Ultra; Soft shadows
Post FX: Low; Medium; High; Ultra
Geometry: Low; High; Very High; Ultra
Vegetation: Low; Medium; High; Ultra
Terrain: Low; Medium; High; Ultra
Water: Low; Medium; High; Very High; Ultra
Environment: Low; High; Ultra
Ambient occlusion: Off; SSAO; SSBC; HBAO+
Anti-aliasing: Off; 2x MSAA; 4x MSAA; 8x MSAA; SMAA; 2x TXAA; 4x TXAA
Godrays: Off; Volumetric fog; Enhanced
Fur: Off/On
Tree relief (tree tessellation): Off/On