Guest OS Support
The other big story over the release candidate versions of Hyper-V is the support for many more guest operating systems. At this time, over 50 guest operating systems have been validated, including Windows 2000 Server, Windows Server 2003, Windows XP, Windows Vista with x86 and x64 support in a variety of multiprocessor scenarios. Additionally, there is support for SUSE Linux Enterprise Server 10 with both Service Pack 1 and 2, in both x86 and x64 architectures. Integration components will also be made available for all of these operating systems, further enhancing their compatibility.
The Hyper-V team runs an extensive battery of tests on each operating system they attempt to validate, ensuring its performance and response to being hosted on a virtual machine is as close to indistinguishable from real, physical hardware as possible. This is all part of the Server Virtualization Validation Program. In addition, OEMs have also qualified more than 214 individual systems to run Hyper-V, and 57 applications are being tested for qualifications by independent software vendors.
I personally tested Windows Server 2003 and Windows Server 2008, both in 32-bit and 64-bit architectures, and found the virtual machines (in my non-scientific examinations) to be quite snappy and realistic. My test system, a Dell Precision Workstation 490 with dual Xeon processors and 4 GB of RAM running Windows Server 2008 (which, of course, is famously named Service Pack 1), ran VMware Workstation and Virtual PC virtual machines quite happily.
But there was a noticeable lag when interacting with the VMs. Application installation would be slow and jerky, using a mouse to cut and paste material from one program to another would take some trundling, and so on. It was usable, but one could certainly tell the difference between using a physical PC and the virtual machine.
In contrast, I was unable to distinguish virtual machines running on Hyper-V from the native hardware with the Integration Components package was installed on each virtual machine.(Integration Components is part of Hyper-V.) Performance over the network, using Hyper-V Manager to route screens and keyboard and mouse responses to and from the virtual machines hosted on another system, was quite good as well.