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
On May 23, 2006, Intel released the dual-core CPU (Xeon branded 5000 series) codenamed Dempsey (product code 80555). Released as the Dual-Core Xeon 5000-series, Dempsey is a NetBurst microarchitecture processor produced using a 65 nm process, and is virtually identical to Intel's "Presler" Pentium Extreme Edition, except for the addition of SMP support, which lets Dempsey operate in dual-processor systems. Dempsey ranges between 2.50 GHz and 3.73 GHz (model numbers 5020–5080). Some models have a 667 MT/s FSB, and others have a 1066 MT/s FSB. Dempsey has 4 MB of L2 Cache (2 MB per core). A Medium Voltage model, at 3.2 GHz and 1066 MT/s FSB (model number 5063), has also been released. Dempsey also introduces a new interface for Xeon processors: LGA 771, also known as Socket J. Dempsey was the first Xeon core in a long time to be somewhat competitive with its Opteron-based counterparts, although it could not claim a decisive lead in any performance metric – that would have to wait for its successor, the Woodcrest.