There is currently a lot of confusion around what the requirements are to run 64Bit guests on 64Bit hosts and the difference between a 64Bit Operating System and 64Bit Virtualization. The following article hopes to expand on this topic and assist with correctly understanding the requirements to run 64Bit Guest machines on a 64Bit machine.

64Bit Operating System vs. 64Bit Virtualization

There is a difference between running a 64Bit operating systems and using 64Bit Virtualization. All computers meeting the listed criteria below can run 64Bit operating systems however they are not necessarily able to handle 64Bit virtualized guest operating systems using application like VirtualBox or Hyper-V. This has to do with limitations on the motherboard.

The requirements to run a 64Bit operating system is as follows:

Processor with EM64T or Intel-64 Extension Enabled

All Dual Core 2.0Ghz and higher processors are 64Bit enabled by default. Therefore any 64Bit operating system will install directly onto the machine and utilise the extensions for 64Bit support. However 32Bit applications will still work on 64Bit operating systems as they emulate 32Bit mode when required. However 32Bit applications cannot access device drivers or core operating systems files directly as these are not backwards compatible for stability reasons.

The requirements to run a 64Bit virtualized operating system is as follows:

Machine running a 64Bit Operating System

To host a 64Bit guest the host machine must be running a 64Bit operating system already.

Virtualization Software

Currently the following virtualization software support 64Bit guests:

• VMWare Workstation (Commercial)

• VMWare Server (Free)

• VirtualBox (Free)

• Hyper-V

• Parallels Desktop for Mac

(VirtualBox has experimental support for 64Bit guests on 32Bit hosts)

Intel Virtualization Technology Support

To hosts 64Bit guests operating systems the motherboard needs to have Intel Virtualization Technology Support enabled in the BIOS. This is a special feature built onto the motherboard and is not supported by all motherboards, and is not on by default. Once this is activated all the above mentioned software will be able to install 64Bit operating systems in a virtual machine. Without these extensions you will not be able to host 64Bit guests, however you are still able to run a 64Bit operating system.