Xeon
Introduced in May 2013, Xeon E3-12xx v3 is the first Xeon series based on the Haswell microarchitecture. It uses the new LGA 1150 socket, which was introduced with the desktop Core i5/i7 Haswell processors, incompatible with the LGA 1155 that was used in Xeon E3 and E3 v2. As before, the main difference between the desktop and server versions is added support for ECC memory in the Xeon-branded parts. The main benefit of the new microarchitecture is better power efficiency.
Xeon
The Xeon E5-16xx processors follow the previous Xeon 3500/3600-series products as the high-end single-socket platform, using the LGA 2011 package introduced with this processor. They share the Sandy Bridge-E platform with the single-socket Core i7-38xx and i7-39xx processors. The CPU chips have no integrated GPU but eight CPU cores, some of which are disabled in the entry-level products. The Xeon E5-26xx line has the same features but also enables multi-socket operation like the earlier Xeon 5000-series and Xeon 7000-series processors.