All virtual machines have a hardware version. The hardware version of a virtual machine indicates the lower-level virtual hardware features supported by the virtual machine, such as BIOS, number of virtual slots, maximum number of CPUs, maximum memory configuration, and other characteristics typical to hardware.

The default virtual machine hardware version of a newly created virtual machine is the most recent version available on the host where the virtual machine is created. If you need to create a virtual machine with a hardware version older than the highest supported in order to increase compatibility, you can use the custom virtual machine creation path. The hardware version of a virtual machine can be lower than the highest version supported by the ESX/ESXi host it is running on if:

You migrate a virtual machine created on an ESX/ESXi 3.x or earlier host to an ESX/ESXi 4.x host.

You create a new virtual machine on an ESX 4.x host using an existing virtual disk that was created on an ESX/ESXi 3.x or earlier host.

You add a virtual disk created on an ESX/ESXi 3.x or earlier host to a virtual machine created on an ESX/ESXi 4.x host.

Virtual machines with hardware versions lower than 4 can run on ESX/ESXi 4.x hosts but have reduced performance and capabilities. In particular, you cannot add or remove virtual devices on virtual machines with hardware versions lower than 4 when they reside on an ESX/ESXi 4.x host. To make full use of these virtual machines, upgrade the virtual hardware as described in the Upgrade Guide.

Virtual Machine Hardware Versions lists virtual machine hardware versions, the ESX/ESXi versions on which they can be created, edited, and run, the vCenter Server versions on which they are fully supported, and a brief description of the hardware version’s capabilities.

Virtual Machine Hardware Versions

Version 7

Version 4

Version 3

Compatible with vCenter Server version

ESX/ESXi 4.x

create, edit, run

create, edit, run

run

vCenter Server 4.x

ESX Server 3.x

create, edit, run

run

VirtualCenter Server 2.x and higher

ESX Server 2.x

create, edit, run

VirtualCenter Server 1.x and higher

Note

Virtual machine hardware version 4 may be listed as VM3 in documentation for earlier versions of ESX and ESXi. Virtual machine hardware version 3 may be listed as VM2 in documentation for earlier versions of ESX.