The official Far Cry Primal system requirements have been revealed on Steam's product page. As you can see below, they're not far beyond the ones of Far Cry 4 even though Ubisoft dropped PlayStation 3 and Xbox 360 for Primal.

　　MINIMUM (Primal):

　　OS: Windows 7, Windows 8.1, Windows 10 (64-bit versions only)

　　Processor: Intel Core i3-550 | AMD Phenom II X4 955 or equivalent

　　Memory: 4 GB RAM

　　Graphics: NVIDIA GeForce GTX 460 (1GB VRAM) | AMD Radeon HD 5770 (1GB VRAM) or equivalent

　　Storage: 20 GB available space

　　Additional Notes: Windows-compatible keyboard, mouse, optional controller

　　For comparison, these were the ones of Far Cry 4:

　　MINIMUM (Far Cry 4):

　　Supported OS: Windows 7 SP1, Windows 8/8.1 (64-bit 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 space

　　The recommended Far Cry Primal system requirements, however, do feature a leap for the Intel CPU and NVIDIA GPU.

　　RECOMMENDED (Primal):

　　OS: Windows 7, Windows 8.1, Windows 10 (64-bit versions only)

　　Processor: Intel Core i7-2600K | AMD FX-8350 or equivalent

　　Memory: 8 GB RAM

　　Graphics: NVIDIA GeForce GTX 780 | AMD Radeon R9 280X or equivalent

　　Storage: 20 GB available space

　　Far Cry 4's, for comparison:

　　RECOMMENDED (Far Cry 4):

　　Supported OS: MS Windows 7 SP1, MS Windows 8/8.1 (64-bit 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

　　Far Cry Primal is due for release on February 23 for PlayStation 4/Xbox One and March 1 for PC.

　　Unlike previous games in the franchise, it will be single player only. You can find out why in a developer's own words, reported three days ago.