New Intel systems have far more I/O bandwidth than previous systems and they have more than anything available from AMD. ARM is not currently competitive if you need to move lots of data in and out of the system.
The current Intel line quad-socket systems will average about 27.25Gbps unless significant work is done to architect the system to connect with processors and PCIe buses. The IOPS performance of the system will, of course, be higher as IOPS is not impacted by QPI bandwidth limitation.
The dual-socket systems are easier to get higher performance, and the average system performance is over 4.25Gbps. So my conclusion is you are better off using dual-socket systems for high I/O bandwidth requirements versus a quad socket. This, of course, is clearly counterintuitive, but is the best strategy given the current Intel architecture.
You will mostly likely see Ivy Bridge server processors in 2013 and the QPI bandwidth will go way up so with Ivy Bridge quad socket systems likely make sense. More on this after the Ivy Bridge serve processor are released.
Henry Newman, is CEO and CTO of Instrumental Inc., a consulting firm that specializes in high-performance computing and storage.