Intel is currently offering two product families of Intel® Xeon® processors that are suited for four sockets: the Intel® Xeon® Processor E5-4600 and E7-4800 product series. This blog is about their difference in terms of memory latency and how to measure it on your own system.
All current Intel® Xeon® processors have integrated memory controllers, i.e. the memory is directly connected to one of the processors. Furthermore, each Intel® Xeon® E7 processor is equipped with 4 Intel® QPI links: