http://theinquisitivegeek.com/blog/?p=3
Apple's EFI has a number of bugs regarding VT activation. On some Mac systems, VT is only enabled on some processor cores. On some Mac systems, VT is not reactivated after waking the system from certain sleep states. Since it is a Mac-specific product, Fusion has workarounds for these issues. The ideal solution is to get an updated EFI release from Apple that fixes these bugs.
In the interim, you can try the following:
Add "hv.enableIfUnlocked = TRUE" to your system-wide VMware configuration file. On Linux hosts, this is /etc/vmware/config. On Windows hosts, try
C:\Documents and Settings\All Users\Application Data\VMware\VMware Workstation\config.ini
or
C:\Users\All Users\Application Data\VMware\VMware Workstation\config.ini
If the firmware leaves VT disabled but does not lock it in this state, this setting should enable VT for you.
(In the interest of full disclosure, I have never tried this, since I have no systems with broken firmware.)
http://communities.vmware.com/message/932302#932302
http://209.85.129.132/search?q=cache:DjxAdVB2UGwJ:discussions.apple.com/thread.jspa%3FthreadID%3D1427832%26tstart%3D29+hyper-v+bootcamp+bios+efi+mac&hl=en&ct=clnk&cd=6 (http://discussions.apple.com/thread.jspa?threadID=1427832&tstart=29)
