Currently there is no solution offered by ESRI to deploy a dual socket server and be in compliance with its base 4 Core licensing since the minimum size of a modern server CPU is now Quad core. What will we do when 8 core is the smallest CPU being sold? ESRI Support gave me several contraditory answers and unacceptable and untested OS hacks but ultimatly the final word was to install it in a virtualized environment (we don't have virtualization yet)or a single processor server (reduces the reliability of the mission critical system).
It is very wrong for a software vendor to dictate a hardware architecture that is operationally incorrect (1 socket on a mission critical server) via its unruly licensing model. Most other vendors (except Oracle) license by the socket or named user.
ESRI needs to change its licensing model to be based on sockets or provide a software solution that limits the number of processors available to the application to comply with the 4 core limit.