Minimum:

OS: Windows 7 64-bit
Processor: 2 GHz Dual Core (Core 2 Duo 2.4 GHz or Althon X2 2.7 GHz)
Memory: 2 GB RAM
Graphics: Graphics card (AMD): DirectX 10.1 compatible with 512 MB RAM (ATI Radeon 3000, 4000, 5000 or 6000 series, with ATI Radeon 3870 or higher performance) Graphics card (NVIDIA): DirectX 10.0 compatible with 512 MB RAM (NVIDIA GeForce 8, 9, 200, 300, 400 or 500 series with NVIDIA GeForce 8800 GT or higher performance)
DirectX: Version 10
Storage: 20 GB available space
Sound Card: DirectX Compatible

Battlefield 3 screenshots