Windows BSOD when all cpu cores enabled

If you have a spare hard disk laying around you could try install a copy of Linux like Ubuntu. After Linux is installed try installing VMware or Virtualbox and see if the error presists. What this would rule out is hardware malfunction.

Another thing you could try but would be much more complex would be to run a copy of VMware ESXi and make the machine into a temporary server and once again see if the problems still presist.

Something that has just crossed my mind, what is the specs of one of you virtual machines?

Are you allocating all system resources to the VMs or are you holding back?

For example I only use 1 vCPU in my VM(s) so there is still one available for the main system, granted I am only running 1 VM at a time but you get the idea.

I have researched this a lot and have found that in production your processor was originally made to be a 6 core proc, it was discovered that one or more cores were unstable or non usable so instead of trashing the die they locked the cores and sold it as a IIx4. They would not sell it as a 5 core and thus selling it as a 4 core proc. I would recommend using it as 5 core but if you see any problems revert back to quad. There ins't a significant performance increase to warrant the headache. Also most of the time when unlocking cores they produce more heat and depending on if you are going to overclock you might need to run @ a lower speed because of the extra core. Its a huge can of worms my friend.