In Windows 8, Microsoft has replaced its previous virtualization solution, Windows Virtual PC, with a more powerful, scalable, and capable solution called Hyper-V. Based on its server-based virtualization technologies, Hyper-V is a better solution for developers, IT pros, and the help desk. But it does lack one crucial capability that made Virtual PC special.

(I’ve been writing about Hyper-V ever since the first version appeared in pre-release form in Windows Server 2008. For a bit of background, you might want to read Windows Server 2008 Hyper-V, Microsoft Hyper-V Server 2008 R2 Preview, and Microsoft Hyper-V Server 2008: The Good, the Bad, And the Ugly. And I’ve covered the Windows 8 pre-release version of Hyper-V in Windows 8 Feature Focus: Client Hyper-V.)

From the perspective of the average Windows 8 desktop user, Hyper-V is a bit of a mystery. Put simply, Microsoft has brought exactly the same virtualization infrastructure from its far more scalable Windows Server product line to the client in Windows 8, giving those who need these capabilities a more compatible and integrated solution. But where Hyper-V forms the basis of Microsoft’s virtualization and cloud computing strategies in Windows Server and in Azure, its purpose in Windows 8 is more constrained.

It comes down to feature set.

With Windows Virtual PC, a free add-on for Windows 7, users could install other OSes in a virtual environment and run that environment, in a window, under Windows 7. They could install applications in those virtual environments, too, providing a way to access solutions that required a different version of Windows, or a different version of IE, or whatever, something that for whatever reason wouldn’t run optimally or at all under Windows 7 natively.

Better still, Windows Virtual PC offered a feature called XP Mode, free for users of Windows 7 Professional, Enterprise, and Ultimate, which included a full working copy of Windows XP with Service Pack 3. But the big deal here is that as you installed applications in the virtual copy of XP, they would be made available through Windows 7’s Start Menu. And you could run these applications, side-by-side, with Windows 7 applications on the Windows 7 desktop. It was a seamless, integrated experience, ideal for those one-off application compatibility issues.

(To learn more, please read Windows 7 Feature Focus: Windows Virtual PC and Windows XP Mode.)

XP Mode is not available in Hyper-V. I asked Microsoft about this during TechEd 2012 and was told that the ability to run virtualized applications side-by-side with native applications on the host desktop was just a happy side-effect of Windows Virtual PC’s architecture: As a so-called type-2 hypervisor—a virtualization solution that runs within the host OS—Windows Virtual PC wasn’t technically as sophisticated as Hyper-V. But it did have this one nicety.

Hyper-V, meanwhile, is a type-0 hypervisor. It runs directly on the PC’s (or server’s) hardware and essentially installs itself “under” Windows 8. This is why Hyper-Vi is more powerful, scalable, and capable than Windows Virtual PC. And since it’s the same code that Microsoft uses in Windows Server, it enables some useful and specific new scenarios. It just doesn’t support XP Mode.

Those who need something like XP Mode can of course look elsewhere. For example, Microsoft offers a product called Microsoft Enterprise Desktop Virtualization, or MED-V, part of the Microsoft Desktop Optimization Pack (MDOP) suite of tools that are available to enterprises through Software Assurance (SA) volume licensing, or to smaller businesses via Windows Intune. MED-V is basically a centralized, managed, and server-based version of Windows Virtual PC, and it lets you deploy virtual application packages (and in the next version, application group packages) to your environment’s PC desktops.

(I’ve written about MED-V a number of times as well. You might want to read MED-V: The Final Piece Of The Vista Compatibility Puzzle? and With MED-V, Microsoft Moves One Step Closer To The Future Of App Compatibility for more information.)

Individuals might consider Oracle VirtualBox, a free virtualization solution that’s very similar to (but more powerful than) Windows Virtual PC. I’ve not tested this, but How-To Geek has published a way to (sort of) make XP Mode work in VirtualBox. VirtualBox is also a good solution for individuals whose PCs don’t have the required hardware to run Hyper-V.

But what about Hyper-V in Windows 8? Why might want to install this solution on their client PC? There are many reasons, including:

OS and software evaluation. Those who would like to evaluate other versions of operating systems (Windows, Linux, whatever) or software applications (perhaps running under specific OS versions) will find that creation a library of virtual environments is far less resource- and cost-prohibitive than doing so on physical hardware.

Testing different software or browser versions. Software and web developers can use Hyper-V to create test environments to see how their solutions work in different OS/web browser versions. So while they may develop an application or web site in Windows 8 with IE 10, they can test it in, say, Windows 7 with IE 9, or Windows 7 with IE 8 as well.

Preparing virtual machines for a server, datacenter, or cloud. IT professionals and administrators who work with virtual machines on servers, in a datacenter, or in the cloud may find it easier to provision and configure those VMs locally, on their PC, and then copy them over to their final destination when complete. Since Hyper-V can connect to multiple machines, deploying a locally-created VM to a server or elsewhere is as simple as using the integrated Move wizard.

Help desk. Anyone who supports other users will benefit from having a library of VMs configured like those of their users so that they can try and replicate issues using the same configurations.

If you’re interested in Hyper-V, be sure to check out Windows 8 Feature Focus: Client Hyper-V. In that article, I describe the solution’s hardware requirements, capabilities, and user interfaces.