Processor Compatibility in Hyper-V R2

With the release candidate version of Windows Server 2008 R2 and Microsoft Hyper-V Server 2008 R2 we have added a new feature called “Processor Compatibility”.  The purpose behind this feature is to allow you to live migrate virtual machines between different processor types (from the same manufacturer) without any downtime.

This functionality is configurable through a simple check box on the processor settings page for the virtual machine. If you select to  enable your virtual machine to Migrate to a physical computer with a different processor version then we make sure that the virtual machine can be migrated.

We do this by hiding advanced processor features from the virtual machine, so it can run on any version of the processor.

Some points of interest:

  • This does not allow you to move between AMD and Intel.  Just between different processors from the same manufacturer.
  • While this has been designed for live migration – it extends to make saved states and snapshots compatible as well.  It also helps if you are just using quick migration.
  • There is no extra hardware requirement for this functionality.  Your processor does not need to have AMD Extended Migration or Intel Flex Migration technology.  There are also no BIOS or hardware changes that you need to make.
  • By enabling this feature you do lose access to some advanced CPU features. The features you lose are as follows:
    • AMD: SSSE3, SSE4.1, SSE4.A, SSE5, POPCNT, LZCNT, Misaligned SSE, AMD 3DNow!, Extended AMD 3DNow!
    • Intel: SSSE3, SSE4.1, SSE4.2, POPCNT, Misaligned SSE, XSAVE, AVX