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
Gulftown or Westmere-EP, a six-core 32 nm architecture Westmere-based processor, is the basis for the Xeon 36xx and 56xx series and the Core i7-980X. It launched in the first quarter of 2010. The 36xx-series follows the 35xx-series Bloomfield uni-processor model while the 56xx-series follows the 55xx-series Gainestown dual-processor model and both are socket compatible to their predecessors.