Recently, Microsoft released an Update Rollup for Hyper-V, designed to resolve known issues with Intel processors and networking problems -
An update rollup package for the Hyper-V role in Windows Server 2008 R2: August 24, 2010
This Update Rollup resolve three known issues that already had individual hotfixes:
Stop error message on a Windows Server 2008 R2-based computer that has the Hyper-V role installed and that uses one or more Intel CPUs that are code-named Nehalem: "0x00000101 - CLOCK_WATCHDOG_TIMEOUT"
The network connection of a running Hyper-V virtual machine is lost under heavy outgoing network traffic on a Windows Server 2008 R2-based computer
"STOP: 0x0000001a" error message on a computer that has an Intel Westmere processor together with the Hyper-V role installed on Windows Server 2008 SP2 or on Windows Server 2008 R2
Other hotfixes, not in the above update rollup, include solutions to known issues with AMD’s processors, Hyper-V Manager and backup & restore issues with Hyper-V:
The computer stops responding or restarts during the Hyper-V Live Migration process in Windows Server 2008 R2
This issue occurs because of erratum 383 in AMD Family 10h processors. This erratum generates a machine check exception. This machine check exception causes the hardware to restart or to stop responding.
Virtual machines are missing in the Hyper-V Manager Console or when you create or start a virtual machine, you receive one of the following error codes: "0x800704C8", "0x80070037" or "0x800703E3"
When you try to create or start a virtual machine on a Windows Server 2008-based computer that has the Hyper-V role installed or on a Microsoft Hyper-V Server 2008 or on a Microsoft Hyper-V Server 2008 R2 computer, you experience one of the following problems…
A Hyper-V update rollup package is available for a computer that is running Windows Server 2008 R2
This update rollup package resolves some issues that occur when you backup or restore Hyper-V virtual machines.
Be sure that your Hyper-V servers are using Windows Update or other patching solution (WSUS, SCCM) to keep your server up to date!
Hope it helps! 