Re: ASRock 990FX Extreme4 + FX8120 - Nested Virtualization
This would be a good read for you. http://communities.vmware.com/docs/DOC-8970
Specifically states ....Unfortunately, this feature does not work on AMD "Bulldozer" CPUs running ESXi 5.0.
although I have not tested and can not confirm.... but the write up seems complete.