I was at a customer meeting recently and got asked the question whether it was possible to populate a server with 1 Terabyte of Memory. The customer is a HPC customer and they perform calculations on very large data sets. The requirement was to be able to have a very large dataset loaded into memory at any one time. Another requirement was that it was on an x86, 4-processor system.
One of the criteria for sizing overall memory capacity is the availability of large capacity DIMMS. The forthcoming Nehalem EX systems will be populated with DDR3 DIMMS and if the memory vendors make 16Gb Quad Rank DIMMS available, then the 1Tbyte of RAM is certainly a possibility.
Numbers of memory sots will vary from OEM vendor to vendor. Early samples of the Nehalem EX systems that I have seen are configured with 8 Memory boards each having 8 DIMM slots. Thus theoretically (and if your wallet can stand it!!) if the servers are populated with 16Gb DIMMS, then 16x8x8 = 1024 Gbyte of Memory.
Check out the press release on Nehalem EX here:-
http://www.intel.com/pressroom/archive/releases/20090526comp.htm
While I am on the subject of large memory capacities in a server....Another interesting development on 2 socket servers are the compute blades which form part of the Cisco UCS solution. The Cisco UCS B-250 M1 Extended Memory Blade Server uses some additional Cisco technology to increase the possible memory up to 384Gb per blade. This is a stunning development in terms of virtualisation capabilities in a 2 socket machine.
More information on the Cisco UCS Blade server can be found here:-