Windows 8 to run on Mobile devices

OK, so from what I have seen of Windows 8 it looks to be 1 OS that can run on both a desktop and mobile device with 2 GUIs. One is designed for touch screen and gesture input and the other is a more traditional destop PC input output config.

I know mobile devices are getting more powerful (my current phone is more powerful than my first Desktop) but the OS must have been really stripped down and use much less resource in order to run on a mobile device.

Therefor I am woring on the basis that Windows 8 mus absolutely fly on a desktop? Just thought I would see if anyone has a more educated view than myself?