Official specs from Steam

Assassin's Creed III system requirements

Minimum and recommended PC specs as listed by the developer on Steam.

Minimum

OS *Windows Vista® (SP2)
Processor2.60 GHz Intel® Core™2 Duo E8200 or 2.60 GHz AMD Athlon™ II X4 620
Memory2 GB
Graphics512 MB DirectX® 10—compliant with Shader Model 4.0 or higher (see supported list)*
DirectX®10
Hard Drive17 GB
SoundDirectX 10—compliant (5.1 surround sound recommended)
Multiplayer256 kbps or faster broadband connection
PeripheralsWindows-compatible keyboard, mouse, optional controller (Xbox 360 Controller for Windows recommended) *Supported Video Cards at Time of Release: AMD Radeon™ HD 4850 / 5000 / 6000 / 7000 series NVIDIA® GeForce® 8800 GT / 9 / 200 / 400 / 500 / 600 series Laptop versions of these cards may work, but are not supported. These chipsets are the only ones that will run this game. For the most up-to-date minimum requirement listings, please visit the FAQ on our support website. Requires a Uplay Account

Recommended

OS *Windows Vista® (SP2)
Processor2.66 GHz Intel® Core™2 Quad Q9400 or 3.00 GHz AMD Phenom™ II X4 940
Memory4 GB
Graphics1024 MB DirectX® 10—compliant with Shader Model 5.0 or higher (see supported list)*
DirectX®10
Hard Drive17 GB
SoundDirectX 10–compliant (5.1 surround sound recommended)
Multiplayer256 kbps or faster broadband connection
PeripheralsWindows-compatible keyboard, mouse, optional controller (Xbox 360 Controller for Windows recommended) *Supported Video Cards at Time of Release: AMD Radeon™ HD 4850 / 5000 / 6000 / 7000 series NVIDIA® GeForce® 8800 GT / 9 / 200 / 400 / 500 / 600 series Laptop versions of these cards may work, but are not supported. These chipsets are the only ones that will run this game. For the most up-to-date minimum requirement listings, please visit the FAQ on our support website. Requires a Uplay Account

FAQ

What graphics card do I need for Assassin's Creed III?

Minimum: 512 MB DirectX® 10—compliant with Shader Model 4.0 or higher (see supported list)*. Recommended: 1024 MB DirectX® 10—compliant with Shader Model 5.0 or higher (see supported list)*.

How much RAM does Assassin's Creed III need?

Assassin's Creed III needs 2 GB at minimum, 4 GB recommended.

How big is Assassin's Creed III?

Assassin's Creed III requires 17 GB.

Does Assassin's Creed III run on Mac or Steam Deck/Linux?

There is no native macOS version. There is no native Linux build (Proton compatibility may vary).