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
At low end of the 3400-series is not a Lynnfield but a Clarkdale processor, which is also used in the Core i3-500 and Core i5-600 processors as well as the Celeron G1000 and G6000 Pentium series. A single model was released in March 2010, the Xeon L3406. Compared to all other Clarkdale-based products, this one does not support integrated graphics, but has a much lower thermal design power of just 30 W. Compared to the Lynnfield-based Xeon 3400 models, it only offers two cores.