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Hardware and firmware requirements for 64-bit guest operating systems (1003945)


This article explains the host machine hardware and firmware requirements for installing virtual machines with 64-bit guest operating systems. For information about installing Guest Operating Systems, see the Guest Operating System Installation Guide.

Note: 64-bit guests are not supported for ESX versions 2.5.x and earlier.


VMware's virtual machine monitor has traditionally used segmentation to provide isolation between the guest operating system and the virtual machine monitor. This is necessary because the guest operating system and virtual machine monitor share the linear address space.

To determine whether or not your CPU is suitable for running 64-bit guest operating systems, VMware distributes a free utility. You can download the tool from our web site: Processor Check for 64-Bit Compatibility .

Note: This utility is provided without support from VMware and does not require ESX/ESXi, VMware Server or VMware Workstation to perform the check.

ESX/ESXi, VMware Workstation, Player, and VMware Server require a 64-bit CPU to run a 64-bit guest operating system.

VMware Fusion requires a 64-bit processor to run a 64-bit guest operating system or to run any Mac OS Guest. Mac OS Guests require hardware virtualization (VT), which VMware supports only on 64-bit processors. The Intel Core Solo and Core Duo processors are 32-bit, but the Core 2 Duo and newer processors are 64-bit.

Additional Information

Note: The information supplied in this section applies to older product versions.

Workstation 5.5 - 6.x, Player, and VMware Server 1.x support virtual machines with 64-bit guest operating systems only on host machines that have one of these supported 64-bit processors:

  • AMD Athlon 64, revision D or later
  • AMD Opteron, revision E or later
  • AMD Turion 64, revision E or later
  • AMD Sempron, 64-bit-capable, revision D or later (experimental support)
  • Intel EM64T VT-enabled processors (experimental support)

Note: In shopping for a processor that is compatible with Workstation or VMware Server 64-bit guests, you may be unable to determine the revision numbers of a given vendor's offering of AMD Athlon 64, Opteron, Turion 64, or Sempron processors. At this time, the only reliable way to determine whether or not any of these processors is a revision supported by VMware software is by noting the manufacturing technology (CMOS). Any of the AMD Athlon 64, Opteron, Turion 64, or Sempron processors whose manufacturing technology is 90nm SOI (.09 micron SOI) is compatible with Workstation or VMware Server 64-bit guests. Using this information, you should be able to determine — with the help of your vendor, or from the AMD web site — whether a particular Athlon 64 or Opteron processor model is compatible with Workstation or VMware Server 64-bit guests.

Note: The preceding link was correct as of June 21, 2012. If you find the link is broken, provide feedback and a VMware employee will update the link.


Segmentation support is missing from the initial AMD64 processors (that is, revision C and earlier) while running in long mode. As a result, AMD64 processors prior to revision D do not have an efficient mechanism for isolating the virtual machine monitor from 64-bit guest operating systems. A limited form of segmentation was reintroduced in long mode, in revision D AMD64 processors. As a result, AMD64 processors must be revision D or later to run 64-bit guest operating systems.

Note: Because AMD Opteron and Turion processors do not ship in revision D, AMD Opteron and Turion 64 processors must be revision E or later to run 64-bit guest operating systems.

When reading AMD's documentation, revisions may be given in decimal format (rather than hexadecimal format). For example, Revision F may also be referred to as Revision 15.


Intel CPUs require EM64T and VT support in the chip and in the BIOS.

Note: If VT is enabled on an ESX host, the vmx flag is found in /proc/cpuinfo.

Intel EM64T CPUs do not have segmentation support in long mode. If the Intel EM64T CPU is VT-capable, it comes with hardware virtualization support (Intel's Virtualization Technology). This hardware virtualization support allows VMware to work around the lack of segmentation, making it possible to run 64-bit guest operating systems on Intel EM64T VT-capable CPUs.

  • Firmware/BIOS support is required to enable Intel Virtualization Technology. Some systems (particularly laptops) do not have the necessary firmware/BIOS support to enable Intel Virtualization Technology, and cannot run 64-bit guest operating systems.
  • In multi-processor systems, all processors must support compatible VT implementations. At a minimum, all processors must implement the same VMCS revision ID. In multi-processor systems with mixed processor steppings, 64-bit guest operating systems may not be supported.
  • Many servers that include CPUs with VT support might ship with VT disabled by default, and VT must be enabled manually. If your CPUs support VT but you do not see this option in the BIOS, contact your system vendor to request a BIOS version that lets you enable VT support.
For additional information, see the VMware Communities article Trouble-shooting Intel VT-x Issues.

See Also

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