- Perf improvements for VMs using pass-through disks will see a substantial performance improvement.
- Installing Hyper-V VMs via network (RIS/PXE/WDS) is greatly improved.
- Support for XP and Vista SP1 guests.
- Partial localization in Japanese and German for testing in those languages.
As of today, you can get the RC 0 off WSUS, since it is a Windows Server 2008 patch. For more info see How to Install Windows Server 2008 Hyper-V Release Candidate.
You'll want to read the Release Notes for This Release of Hyper-V.
You can find the Hyper-V manager mmc here:
NOTE: Virtual machines that were created on the beta version of the Hyper-V role do not start after the Hyper-V role is updated to a later version. You can use the virtual hard disk (.vhd) files. However, the virtual machine configuration settings must be re-created. Stepwise instructions are in KB 949222 (http://support.microsoft.com/kb/949222/)