The server that has multiple CPUs with different CPU revision and stepping is no boot after Hyper-V role is enabled


You recently install a Windows Server 2008 R2 and patched SP1. The server (typically HP server) has multiple Intel CPUs, e.g. two Intel (R) Xeon(R) CPU 5160 3.00GHz.

You then enable the Hyper-V role, it required a reboot. But after reboot, the system didn't boot up, it just stayed in black screen.

Root cause:

Although the CPUs are identical, the revision or stepping are different. If one is revision 'CD' (stepping is 6) and the other is revision 'B9' (stepping is B), the system is not booting up with Hyper-V enabled.


Replace the CPU and make sure all CPU are identical with same revision and stepping.

More information:

To check CPU information, run WBEMTEST and enter the query "Select * from Win32_Processor" (without the quotes) and click on the Apply button.


Comments (5)

  1. Mike Crowley says:

    Would you mind commenting on this post?…/ac75a2b0-d8b9-4347-9c8e-12592a0b2b9d

    I didn't have a problem with Win2k8 R2 SP1, but am having an issue where the 2nd CPU won't start in Win 2012, and I'm not sure if its related.

  2. Christian says:

    Very good solution 🙁 … spend hundreds of dollars for new cpu … only because someone is too crazy to write good software ??!! .. why can it work without the SP1 ?! … microsoft make faulty software and we can pay for it – very good solution !!!!

  3. Josiah says:

    I ran into this issue on one of my HP Proliant DL380 G5 servers running Hyper-V.  One of the CPUs had been replaced about six months ago (apparently with a different stepping) and everthing had been running fine.  This week I went to upgrade the BIOS to the latest HP and it hung on the black screen.  I noticed that turning Intel Virtualization allowed me to boot, but that didn't do me any good since this is a Hyper-V host.  The solution was exactly as you described…I had HP swap the processor out the matching stepping and everything works fine.

  4. Bfrustrated says:

    This is so frustrating!!  

    2 days of my life I will not get back . . ..

  5. Damn it Intel says:

    I hate Intel not willing to replace one of my CPUs as the other!

    I hate the steppings.

    I hate newegg that sold me two CPUs with different steppings.

    I cannot use HyperV on Windows Server 2012!

    As always, the products are just outside of the warranty!!

Skip to main content