Windows Server 2008: To keep things stable, you need new hardware

The quickest way to make everything work well together is to run WS2K3 applications in a virtual machine, or a cluster of such VMs, managed through the new Hyper-V thin hypervisor in WS2K8, Visse explained. But to get that accomplished, you really need CPUs that have the wherewithal to support Hyper-V.
"You're going to get a lot more bang for your buck if you run a hypervisor on that new hardware," Visse stated. For instance, big businesses that are exploring the possibilities of using virtualization for server consolidation -- running the same workload more efficiently on fewer CPUs -- will be looking to the hypervisor capability built into new AMD and Intel CPUs, rather than the limitations of software-centric VM environments.
"So I think a lot of people will bring new hardware in to do consolidation, said Visse, perhaps a little hopefully. "That doesn't mean they'll throw everything out that they have, but they may repurpose those servers and do something else with them. They may still do some consolidation of those [older systems], because you can run virtualization on some of those little boxes. But as far as pure performance and total bang for the buck, the total number of VMs that you can get onto a box, you want to have the thin hypervisor layer and running your OSes on top. You can only really do that if you have a virtualization-enabled chip."
Thus the serpentine thread that weaves together two seemingly contradictory appeals to the customer, is laid out by Microsoft with respect to Windows Server 2008: You can only continue to have peace on the surface by means of a systematic upheaval at the core. It's certainly the type of argument that has worked well for Microsoft before.