Da
http://www.microsoft.com/windows/win.../beta-faq.aspx :
Windows 7 Beta recommendation:
* 1 GHz 32-bit or 64-bit processor
* 1 GB of system memory
* 16 GB of available disk space
* Support for DirectX 9 graphics with 128 MB memory (to enable the Aero theme)
* DVD-R/W Drive
* Internet access