Windows 8 Consumer Preview works great on the same hardware that powers Windows 7:
Processor: 1 gigahertz (GHz) or faster
RAM: 1 gigabyte (GB) (32-bit) or 2 GB (64-bit)
Hard disk space: 16 GB (32-bit) or 20 GB (64-bit)
Graphics card: MicrosoftDirectX 9 graphics device or higher
Additional requirements to use certain features:
To use touch, you need a tablet or a monitor that supports multitouch.
To access the Windows Store and to download and run apps, you need an active Internet connection and a screen resolution of at least 1024 x 768.
To snap apps, you need a screen resolution of at least 1366 x 768
learn more and download the Windows 8 Consumer Preview