The Xeon /ˈziːɒn/ is a brand of x86 microprocessors designed, manufactured, and marketed by Intel Corporation, targeted at the non-consumer workstation, server, and embedded system markets. Despite such disadvantages, Xeon processors have always had popularity among users, mainly due to higher core count potential. Because most Intel Xeon CPUs lack an integrated GPU, systems built with such integrated GPU lacking processors require a discrete graphics card if a VDU output is desired, the Xeon brand has been maintained over several generations of x86 and x86-64 processors. Older models added the Xeon moniker to the end of the name of their corresponding desktop processor, the Xeon CPUs generally have more cache than their desktop counterparts in addition to multiprocessing capabilities. The first Xeon-branded processor was the Pentium II Xeon and it was released in 1998, replacing the Pentium Pro in Intels server lineup. The Pentium II Xeon was a Deschutes Pentium II with a full-speed 512 kB,1 MB, 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 die fabricated in a 0.35 µm four-layer metal CMOS process, 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, in 1999, the Pentium II Xeon was replaced by the Pentium III Xeon. The product codes for Tanner mirrored that of Katmai,80525, the second version, named Cascades, was based on the Pentium III Coppermine core. To improve this situation, Intel released another version, officially also named Cascades and that came in two variants, with 1 MB or 2 MB of L2 cache. Its bus speed was fixed at 100 MHz, though in practice the cache was able to offset this, the product code for Cascades mirrored that of Coppermine,80526. In mid-2001, the Xeon brand was introduced, the initial variant that used the new NetBurst microarchitecture, Foster, was slightly different from the desktop Pentium 4. It was a decent chip for workstations, but for server applications it was almost always outperformed by the older Cascades cores with a 2 MB L2 cache, combined with the need to use expensive Rambus Dynamic RAM, the Fosters sales were somewhat unimpressive. This improved performance slightly, but not enough to lift it out of third place and it was also priced much higher than the dual-processor versions. The Foster shared the 80528 product code with Willamette, in 2002 Intel released a 130 nm version of Xeon branded CPU, codenamed Prestonia. It supported Intels new Hyper-Threading technology and had a 512 kB L2 cache and this was based on the Northwood Pentium 4 core. A new server chipset, E7500, was released to support this processor in servers, the Prestonia performed much better than its predecessor and noticeably better than Athlon MP
Image: Intel xeon inside
450 MHz Pentium II Xeon with 512 KByte L2 cache: The cartridge cover has been removed.