I have seen that some manufacturers have Servers on the market, based on Dual Intel Xeon 5600 Series CPU's. These Servers can support up to 192GB of Memory. From reading through the Xeon 5600 CPU documents, I think they suggest the Xeon 5600 has an Address BUS of 36 bits, and I don't see any reference to Address Tagging lines (now I may have this wrong). 36 bits equates to 64GB, hence a Dual CPU equates to 128GB. If my understanding is correct, I do not understand how these systems address between 128GB and 192GB.
I am sure I must be missing something, and welcome some enlightenment.
I have used this document to base this discussion on.