VMware Workstation and VMware Server require a 64-bit CPU to run a 64-bit guest operating system. While it is theoretically possible to emulate a 64-bit instruction set on 32-bit hardware, doing so results in unacceptable performance degradation.

[http://vmware.com/info?id=152]

[http://kb.vmware.com/selfservice/microsites/search.do? language=en_US&cmd=displayKC&externalId=1901]