Virtual Box - Install WIndows 8.1 x64 Eval on OS X host

I recently tried to create a Windows 8.1 VM using virtual box on my Macbook pro, but ran into an error immediately after boot:

Your PC needs to restart.
Please hold down the power button.
Error code: 0x000000C4

The solution is here: http://4sysops.com/forums/topic/windows-server-2012-r2-on-virtual-box-error-0x000000c4/ but it needs to be tweaked slightly for OS X.

Open the terminal and do the following, making sure to use the name of your Win 8 vm instead of [name]

cd VirtualBox\ VMs

VBoxManage setextradata [name] VBoxInternal/CPUM/CMPXCHG16B 1

 That's it!