For those who came in late Chipzilla jacked up its Xeons by scaling them scaling up to eight sockets using Intel's on-chip NUMA links. Biggish Blue has replied by expanding its high-end Power E880 machines, which scale out to a maximum of 16 sockets and 16 TB of main memory.
In an interesting article in the Platform http://www.theplatform.net/2015/05/11/power8-iron-to-take-on-four-socket-xeons/ , IBM accidently leaked details of these high-end boxes at its Edge2015. It was supposed to save them until its Las Vegas this week.
The final machine to be added to the Power8-based Power Systems lineup from Big Blue is the Power E850, and it is a four-socket machine that is aimed at HP, Dell, Oracle, Fujitsu, NEC, and others that employ Intel's Xeon E7-4800 v3 CPUs, which similarly support four-way NUMA clustering in their hardware.
The Power E850 includes some capacity-on-demand features that up until now have only been available on larger Power Systems machines. With capacity on demand, IBM ships a box loaded with processors and main memory and allows customers to activate it as needed either permanently or temporarily on a daily or monthly basis with utility pricing.
The base Power E850 system ships with two processors and a full memory complement (based on 16 GB, 32 GB, or 64 GB memory sticks) as a base, and customers active Power8 cores and memory in 1 GB increments.
The chips are based on IBM's "Murano" dual-chip module, which puts two linked half-cored Power8 chips into a single Power8 socket. The smaller chip has a high yield than a larger chip and IBM's 22 nanometer copper/SOI process does not have the volume advantages of Intel's 22 nanometer Tri-Gate process, which is used to make the Haswell-EX Xeon E7 v3 processors.
DCM variants of the Power8 chips have more I/O capacity on their PCI-Express controllers, at 48 lanes per second instead of the 32 lanes per socket that are used in the single-chip variants of the Power8 chips used in the high-end Power E870 and Power E880 systems, which respectively scale to eight and sixteen sockets in a single image.
We expect to hear more about Biggish Blue's plans later this week.