Processor Compatibility in Hyper-V R2

Processor Compatibility in Hyper-V R2

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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


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  • Please add 5 and 4 and type the answer here:
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  • I was trying to do a P2V on a really old XP machine today and ran into the 512Mb Memory requirement - is there any chance that will ever be reduced?  There are lots of 256Mb machines still chugging around that would be great to turn into VMs.

  • is it possible to live migrate between a server with a 4 core intel and a server with a 2 core intel proccessor?

  • Hi

    Will this always disable ALL the features you mentioned? Or will it look for the lowest common features set within the group of Hyper-V hosts?

    In other words, if all my Hyper-V hosts support SSE4.1 will the VM still see SSE 4.1?


  • Robert -

    Unfortunately this is unlikely to change.  We use WinPE for our offline P2V - which requires 512MB of ram.

    Lucas Zandvliet -

    Maybe.  If the VM has 2 (or 1) virtual processors - yes, it will just work.  If it has 4 virtual processors then it will fail as the processor to core ratio would need to change.

    Gabrie -

    This is an "all or nothing" setting.



  • I have VM w2008R2 on w2008R2, with procesor Dual_Core AMD Opteron. Is there any possibility to migrate the VM to a new server with INTEL? If not, can I choose any processor from AMD? Do you see some other adversity?

  • I have a server motherboard with 2 dual core Xeon processors that are not listed as compatible, will this allow me to turn on Hyper V on this server?

  • Enabling this feature, will impact CPU performance to an application like SQL or Exchange?

  • I have two windows server 2008 R2 hyper-v hosts. one has 8 x 2.33Ghz Xeon. The other has 4 x 2.33Ghz Xeon. The checkbox on the vm IS TICKED, but yet STILL it says the processors are different!!!!


  • i have Intel DG31 PR Motherboard and Intel E7200,2.53GHz Core 2 Duo Processor and 2 GB DDR2 Ram,but i cannot install Hyper-V in windows Server 2008R2.What is the processor's configuration,plz help me

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