Compatibility problem with kvm64 CPU type RRS feed

  • General discussion

  • (copied from Microsoft Communities)

    It appears Windows 8.1 Preview has a compatibility problem with the kvm64 CPU type used by Proxmox 3.0 (http://pve.proxmox.com/wiki/Main_Page) and other KVM (http://www.linux-kvm.org/page/Main_Page) systems.   When booting from the DVD the fish gets displayed before a "Your PC needs to reboot" message appears and the VM is rebooted. Windows booted successfully after changing the emulated CPU type to Nehelem, but since Windows Server 2003, 2008, 2008 R2 and 2012 all work with kvm64 it appears this is a regression.

    I was trying to install 8.1 on a blank 128GB virtual disk.

    • Edited by bcran Thursday, July 18, 2013 7:21 PM Add more details
    Thursday, July 18, 2013 7:18 PM

All replies

  • Windows 8.1 requires CMPXCHG16B

    This also causes failures for Virtualbox:


    try if you can activate this feature for KVM.

    "A programmer is just a tool which converts caffeine into code"

    Thursday, July 18, 2013 7:23 PM
  • Thanks! I guess kvm64 is the emulation that's totally compatible with all x64 CPUs so I'll need to continue using Nehelem or newer.

    Bruce Cran

    Thursday, July 18, 2013 7:28 PM
  • Hi,

    How’s everything going? Please feel free to let use know.


    Vincent Wang
    TechNet Community Support

    Monday, July 22, 2013 3:04 AM