Microsoft recommend the following specifications for a system running Windows 7:
  • 1GHz processor (32 or 64-bit)
  • 1GB of main memory
  • 16GB of available disk space
  • Support for DX9 graphics with 128MB of memory (for the Aero interface)
However, it is technically possible to run Windows 7 with a lower specification PC with as little as 256MB RAM, 8MB graphics memory and a 500Mhz PIII CPU [Source]. This would not be recommended, but it demonstrates the scalability of Windows 7 compared to Vista.
Ian, Apr 14, 2009