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 E3-12xx line of processors, introduced in April 2011, uses the Sandy Bridge chips that are also the base for the Core i3/i5/i7-2xxx and Celeron/Pentium Gxxx products using the same LGA 1155 socket, but with a different set of features disabled. Notably, the Xeon variants include support for ECC memory, VT-d and trusted execution that are not present on the consumer models, while only some Xeon E3 enable the integrated GPU that is present on Sandy Bridge. Like its Xeon 3400-series predecessors, the Xeon E3 only supports operation with a single CPU socket and is targeted at entry-level workstations and servers. The CPUID of this processor is 0206A7h, the product code is 80623.