I've been wondering for a while if there is a way to couple CPU's together as in the SLI or Crossfire technology in graphics cards. That would be very expensive, though... I'm just asking out of curiosity, since I would never be able to afford that.
Multi cpus is really only for workstations or servers as there is no need for such cpu power for games. Some of the cpus don't require ecc ram. There isn't a technology to be able to use multi cpus. As long as the software supports multithreading, the os will handle the cpu/core workload distribution.