Windows 8 will run on ARM. Now, what is ARM? ARM stands for Advanced RISC Machine or Acorn RISC Machine energy-efficient. ARM processors are very light-weight and are most commonly used in mobile and embedded devices, such as Windows Embedded.
Many embedded systems already run on Windows Embedded (Windows Embedded CE or Windows CE). Now that Windows 8 will support ARM Windows 8 can be run very effectively on mobile devices such as slate PC’s and tablet PC’s similar to the iPad. This is no surprise. Rumors spread during the last days that Microsoft plans to present a tablet PC that runs on Windows 8 at the CES. Even if it turns out not to be true, this will be possible in the future and will most likely be one of the biggest advantages of Windows 8.
Windows 7 is not running well on mobile devices. HP did not cancel the Windows 7 Slate PC that was announced at the last CES (2010) without reason. (HP is now using their own palm OS on their own mobile devices)
Running Windows 8 on ARM architecture alongside x86 is a big step and could open the doors for a mobile Windows experience with everything we like and use on Windows, including all Office products and Windows LIVE services.