According to GameSpot, Ubisoft may have leaked the specs for the PC version of Assassin’s Creed III early (seeing as how the post has been removed from Ubisoft’s site). Here’s what was listed:
Supported OS: Windows Vista (SP2)/Windows 7 (SP1) / Windows 8
Processor: 2.66GHz Intel Core2 Duo E6700 or 3.00GHz AMD Athlon 64 x2 6000+ or better recommended
RAM: 2GB (4GB recommended)
Video card: 512MB DirectX 9.0c-compliant with Shader Model 4.0 or higher
Sound card: DirectX 9.0c-compliant (5.1 surround sound recommended)
DVD-ROM: Dual-layer drive
Hard drive space: 17GB
Peripherals supported: Windows-compatible keyboard, mouse, optional controller (Xbox 360 Controller for Windows recommended)
Multiplayer: 256Kbps or faster broadband connection
Supported video cards at time of release:
AMD Radeon HD 3870 / 4000 / 5000 / 6000 / 7000 series or better
Nvidia GeForce 8600 GT / 9 / 100 / 200 / 300 / 400 / 500 / 600 series or better