Below are the bare minimum system specs required to power George Washington, Benjamin Franklin, Thomas Jefferson, the Knights Templar, early Boston and New York, dogs, boats, Captain Kidd’s lost pirate treasure, the Animus, and a bloke named Desmond.
Supported OS: Windows Vista (SP2) / Windows 7 (SP1) / Windows 8
Processor: 2.66 GHz Intel Core2 Duo E6700 or 3.00 GHz AMD Athlon 64 X2 6000+ or better recommended
RAM: 2 GB (4 GB recommended)
Video Card: 512 MB DirectX 9.0c-compliant with Shader Model 4.0 or higher (see supported list)*
Sound Card: DirectX 9.0c-compliant (5.1 surround sound recommended)
DVD-ROM: Dual-layer drive
Hard Drive Space: 17 GB
Peripherals Supported: Windows-compatible keyboard, mouse, optional controller (Xbox 360 Controller for Windows recommended)
Multiplayer: 256 kbps 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
(Laptop versions of these cards may work, but are not supported. These chipsets are the only ones that will run this game.)
You might scoff at 17 GB, but remember that contained within is the entire Eastern US seaboard.
Check the Assassin’s Creed III System Requirements here.