From MS technet.
What is Windows To Go?
Windows To Go is a new feature for enterprise users of Windows 8 that
enables users to boot a full version of Windows from external USB
drives on host PCs.
Does Windows To Go rely on virtualization?
No, Windows To Go is a native instance of Windows 8 that runs from a
USB device. It is just like a laptop hard drive with Windows 8 that
has been put into a USB enclosure.
Is Windows To Go supported on both USB 2.0 and USB 3.0 drives?
No, Windows To Go is supported on USB 3.0 drives that are certified
for Windows To Go.
Is Windows To Go supported on USB 2.0 and USB 3.0 ports?
Yes. Windows To Go is fully supported on either USB 2.0 ports or USB
3.0 ports on PC’s certified for Windows 7 or Windows 8.
How do I identify a USB 3.0 port?
USB 3.0 ports are usually marked blue or carry a SS marking on the
Does Windows To Go run faster on a USB 3.0 port?
Yes. Since USB 3.0 offers significantly faster speeds than USB 2.0, a
Windows To Go drive running on a USB 3.0 port will operate
Can the user self-provision Windows To Go?
Yes, if the user has administrator permissions they can self-provision
a Windows To Go drive using the Windows To Go Creator wizard which is
included in Windows 8 Enterprise edition. Additionally, the Community
Technology Preview (CTP) of Service Pack 1 for System Center 2012
Configuration Manager includes support for user self-provisioning of
Windows To Go drives. Configuration Manager 2012 SP1 CTP can be
downloaded for evaluation from the Microsoft Download Center.