Ubisoft released the PC specs for Far Cry 4. Take a look below.

.

Far Cry 4 system requirements:

.

Minimum:

Operating system: Windows 7 SP1, Windows 8/8.1 (64bit versions only)
Processor: Intel Core i5-750 @ 2.6 GHz or AMD Phenom II X4 955 @ 3.2 GHz
Memory: 4GB
Video card: NVIDIA GeForce GTX 460 or AMD Radeon HD5850 (1GB VRAM)Direct X: Version 11
Hard Drive: 30 GB available spaceSound Card: DirectX 9.0c compatible sound card with latest drivers

.

Recommended:

Operating system: Windows 7 SP1, Windows 8/8.1 (64bit versions only)
Processor: Intel Core i5-2400S @ 2.5 GHz or AMD FX-8350 @ 4.0 GHz or better
Memory: 8GB
Video card: NVIDIA GeForce GTX 680 or AMD Radeon R9 290X or better (2GB VRAM)Direct X: Version 11
Hard Drive: 30 GB available space
Sound Card: DirectX 9.0c compatible sound card with latest drivers

.

Source: dsogaming.com