Xeon
The first Xeon-branded processor was the Pentium II Xeon (code-named "Drake"). It was released in 1998, replacing the Pentium Pro in Intel's server lineup. The Pentium II Xeon was a ""Deschutes"" Pentium II (and shared the same product code: 80523) with a full-speed 512 kB, 1 MB, or 2 MB L2 cache. The L2 cache was implemented with custom 512 kB SRAMs developed by Intel. The number of SRAMs depended on the amount of cache. A 512 kB configuration required one SRAM, a 1 MB configuration: two SRAMs, and a 2 MB configuration: four SRAMs on both sides of the PCB. Each SRAM was a 12.90 mm by 17.23 mm (222.21 mm²) die fabricated in a 0.35 µm four-layer metal CMOS process and packaged in a cavity-down wire-bonded land grid array (LGA). The additional cache required a larger module and thus the Pentium II Xeon used a larger slot, Slot 2. It was supported by the 440GX dual-processor workstation chipset and the 450NX quad- or octo-processor chipset.
Xeon
Introduced in September 2014, Xeon E5-16xx v3 and Xeon E5-26xx v3 series use the new LGA 2011-v3 socket, which is incompatible with the LGA 2011 socket used by earlier Xeon E5 and E5 v2 generations based on Sandy Bridge and Ivy Bridge microarchitectures. Some of the main benefits of this generation, compared to the previous one, are improved power efficiency, higher core counts, and bigger last level caches (LLCs). Following the already used nomenclature, Xeon E5-26xx v3 series allows dual-socket operation.