Minimum: OS: Operating System: Windows XP SP3 Processor: 2 GHz Intel Dual Core Processor Memory: 2GB RAM (XP), 2GB RAM (Vista) Graphics: NVIDIA GeForce 8500/ATI Radeon HD 2600 (256 minimum) DirectX®: 9.0c Hard Drive: 20GB free hard disk space Sound: DirectX 9.0c compatible Other Requirements: Initial installation requires one-time internet connection for Steam authentication; software installations required (included with the game) include Steam Client, DirectX 9, Microsoft.NET 4 Framework, Visual C++ Redistributable 2005, Visual C++ Redistributable 2008, Visual C++ Redistributable 2010, and AMD CPU Drivers (XP Only/AMD Only)