Minimum requirements for Battlefield 3
OS: Windows Vista or Windows 7
Processor: Core 2 Duo 2.4 GHz or Althon X2 2.7 GHz
Graphic card: DirectX 10 or 11 compatible Nvidia or AMD ATI card, ATI Radeon 3870 or higher, Nvidia GeForce 8800 GT or higher.
Graphics card memory: 512 MB
Sound card: DirectX compatibl sound card
Hard drive: 15 GB for disc version or 10 GB for digital version
Copy and pasted from the bf3 wiki, that's the absolute minimun hardware that you can use to play. So I imagine anything higher than this would work out better.