Scalability information of Intel® Xeon® Processors
This page describes how 4S is different from S4S for scalability of Intel® Xeon® Processors.
An Intel® Xeon® processor that supports 4S or S4S scalability can be used in a server with up to four sockets. There is no performance difference between a 4S and S4S when used in a four-socket system.
The S prefix in S4S scalability means the processor could be used with a server that utilizes third-party node controller technology to expand the number of sockets beyond the four sockets.
Node controller technology may be referred to as eXternal Node Controller technology or XNC. Check with your server manufacturer whether they support node controller technology for larger configurations. One example of such a server is a supercomputer.