Sega have revealed the official minimum and recommended specs for the PC version of Alien: Isolation.
Minimum PC Specifications are:
Operating System: Windows 7 (32bit)
Processor: 3.16Ghz Intel Core 2 Duo E8500
RAM: 4GB RAM
Hard Drive: 35GB required for installation
Video Card: 1GB DirectX® 11 (AMD Radeon HD 5550 or Nvidia GeForce GT 430)
Broadband Internet Connection
Recommended PC Specifications are:
Operating System: Windows 7 (64bit)
Processor: AMD: Phenom II X4 955 - 4 Core, 3.2 GHz or INTEL: Core 2 Quad Q9650 - 4 Core, 3.0 Ghz
RAM: 8GB RAM
Hard Drive: 35GB required for installation
Video Card: 2GB DirectX® 11 (AMD GPU: AMD Radeon R9 200 Series or Nvidia gpu: GeForce GTX660)
Broadband Internet Connection