Overview"Client Hyper-V is the virtualization technology built into Windows 8. Client Hyper-V is the same virtualization technology previously available only in Windows Server. A similar functionality in Windows 7 is called Windows XP Mode.
Client Hyper-V enables you to run more than one 32-bit or 64-bit x86 operating system at the same time on the same host computer. But instead of working directly with the computer’s hardware, the operating systems run inside a virtual machine (VM).
Hyper-V enables developers and IT professionals to easily maintain multiple test environments and provides a simple mechanism to quickly switch between these environments."
Additional Information :
Windows 8 Feature Focus : Client Hyper-V : http://winsupersite.com/article/windows8/windows-8-feature-focus-client-hyperv-142889?utm_source=twitterfeed&utm_medium=twitter
Windows 8: Client Hyper-V and Why It Matters (Channel 9) : http://channel9.msdn.com/Series/Reimagining-Windows-An-In-Depth-Look-at-Windows-8-for-the-Enterprise/Episode-6-Windows-8-Client-Hyper-V-and-Why-It-Matters