Here are the official PC specifications requirements for Batman: Arkham Knight – Requirements.

MINIMUM:
OS: Win 7 SP1, Win 8.1 (64-bit Operating System Required)
Processor: Intel Core i5-750, 2.67 GHz | AMD Phenom II X4 965, 3.4 GHz
Memory: 6 GB RAM
Graphics: NVIDIA GeForce GTX 660 | AMD Radeon HD 7870 – 2 GB Memory Minimum
DirectX: Version 11
Network: Broadband Internet connection
Hard Drive: 45 GB available space

RECOMMENDED:
OS: Win 7 SP1, Win 8.1 (64-bit Operating System Required)
Processor: Intel Core i7-3770, 3.4 GHz | AMD FX-8350, 4.0 GHz
Memory: 8 GB RAM
Graphics: NVIDIA GeForce GTX 760 – 3 GB Memory Recommended
DirectX: Version 11
Network: Broadband Internet connection
Hard Drive: 55 GB available space