Xeon
The Xeon is Intel's name for its server-class PC microprocessors intended for multiple-processor machines. The name has been kept over several generations of processors. Older models added the name Xeon to the end of the name of the corresponding standard range but the more recent models have just used the name Xeon on its own. Xeon chips generally have more cache and support larger multiprocessor configurations than their desktop counterparts.
Pentium II Xeon
The first Xeon processor was released in 1998 as the Pentium II Xeon as the replacement of the Pentium Pro. The Pentium II Xeon was based on the P6 microarchitecture and used either a 440GX (a dual-processor workstation chipset) or 450NX (quad-processor, or oct with additional logic) chipset, and differed from the desktop Pentium II in that it had a full-speed, off-die L2 cache. It also used a larger slot known as slot 2 Cache sizes were 512 kB, 1 MB and 2 MB, and it used a 100 MHz bus.
Pentium III Xeon
In 1999, the Pentium II Xeon was replaced by the Pentium III Xeon. The initial version (Tanner) was no different from its predecessor, save the addition of SSE and a few cache controller enhancements found in the Pentium III. The second version (Cascades) was somewhat more controversial, in that while it had a 133 MHz bus it only had a 256 kB on-die L2 cache - in other words, there was no difference between it and the desktop Pentium III. In order to remedy the situation somewhat, Intel released a second version (also called Cascades, but often suffixed to Cascades 2 MB to differentiate between it and the 256 kB version) that came in two variants: with 1 MB or 2 MB of L2 cache. The bus speed on these models was fixed at 100 MHz , though in practice the cache was able to offset this.
Xeon & Xeon MP (32-bit)
The Xeon (dropping "Pentium" from the name) was introduced in mid-2001. The initial variant that used the new NetBurst architecture, Foster, was slightly different from the desktop Pentium 4. It served as a decent workstation chip, but it was almost always outperformed in server applications by the older Cascade 2 MB core and AMD's Athlon MP. Combined with the need to use expensive Rambus Dynamic RAM (RDRAM), the Foster's sales were somewhat unimpressive.
Foster only supported 2 processors, so a second version (Foster MP) was introduced with a 1 MB L3 cache. This improved performance slightly, but not by enough to lift it out of third place. It was also much more expensive than the dual-processor (DP) versions.
In 2002 a 130 nm version of the Xeon (this time codenamed Prestonia) was released, now supporting Intel's new Hyper-Threading technology and having a 512 kB L2 cache. A new server chipset, E7500 (which allowed the use of dual-channel DDR SDRAM) was released to support this processor in servers, and shortly afterwards the bus speed was boosted to 533 MHz (accompanied by new chipsets; the E7501 for servers and the E7505 for workstations). The new Xeon performed much better than its predecessor and noticeably better than Athlon MP. The support of new features in the E75xx series also gave it a key advantage over the Pentium III Xeon and Athlon MP (both stuck with rather old chipsets), and it quickly became the top-selling server/workstation processor.
The Xeon MP version of the Prestonia was the Gallatin, which had an L3 cache of 1 MB or 2 MB. This version also performed a lot better than Foster MP, and was popular in servers. Later on, Intel's experience with the 130 nm process allowed them to port the Xeon over to the Gallatin core and also allowed a Xeon MP with 4 MB cache.
Xeon & Xeon MP (64-bit)
Due to a severe lack of success with Intel's Itanium and Itanium 2 processors, the 90 nm version of the Pentium 4 (Prescott) was built with support for 64-bit instructions (called EM64T by Intel, though it was much the same as AMD's AMD64 instruction set), and a Xeon version codenamed Nocona was released in 2004. Released with it were the E7525 (workstation), E7520 and E7320 (both server) chipsets, which added support for PCI Express, DDR-II and Serial ATA. Generally speaking the Xeon was noticeably slower than AMD's Opteron, though it could also be much faster in situations where Hyper-Threading came into play.
A slightly updated core called Irwindale was released in early 2005, differing from Nocona in having twice the L2 cache and the ability to reduce its clockspeeds in situations that didn't need much processing power. However, performance numbers generated though independent tests which have been conducted show the Irwindale still outperformed by the AMD Opteron processor.
64-bit Xeon MPs were introduced in April 2005. The cheaper version was Cranford, an MP version of Nocona. The more expensive version was Potomac; a Nocona with an 8 MB L3 cache.
Xeon & Xeon MP (dual-core)
Intel released the first dual-core Xeon, codenamed Paxville DP, on 10 October 2005. Paxville DP is a dual-core version of Irwindale, with 4 MB of L2 Cache (2 MB per core). The one Paxville DP model that has been released runs at 2.8 GHz and features an 800 MHz (200 MHz quad-pumped) front side bus.
A Xeon MP version, codenamed Paxville, has been released on 1 November 2005. There are two versions: one with 2 MB of L2 Cache (1 MB per core), and one with 4 MB of L2 (2 MB per core). Paxville is called the Xeon MP 7000-series. Paxville ranges between 2.67 and 3.0 GHz (model numbers 7020-7041), with some models having a 667 MHz (166 MHz quad-pumped) FSB, and others having an 800 MHz FSB.
Future versions
Dempsey
Similar to Paxville DP, except using a 65 nm process, making it virtually identical to Intel's "Presler" Pentium D, except for SMP support. It will be called the Xeon DP 5000-series and will likely use a new interface, Socket J, also called LGA 771. Dempsey will range between 2.5 and 3.46 GHz (model numbers 5020-5070). Some models will have a 667 FSB, and others will have a 1066 MHz (266 MHz quad-pumped) FSB. Dempsey will have 4 MB of L2 Cache (2 MB per core). A Medium Voltage model, at 3.2 GHz and 1066 MHz FSB (model number 5063), will also be released.
Sossaman
A version of the dual-core Core Duo that supports multi-processor configurations. Rumoured to use a new interface, Socket 480. Will be called the Xeon DP, but might not receive model numbers. Will launch with a Low Voltage 2.0 GHz model and an Ultra Low Voltage 1.67 GHz model. Like Yonah, Sossaman will feature a 667 MHz FSB and 2 MB of L2 Cache shared between the cores.
Tulsa
An improved version of Paxville, built on a 65 nm process, with more cache. Tulsa is rumoured to have 2 MB of L2 (1 MB per core) and 16 MB of L3 shared between the cores. Will likely use the same LGA 771 interface as Dempsey.
Woodcrest
A dual-core processor, based on Intel's upcoming Merom and Conroe cores, using a new microarchitecture, not based on either the existing Pentium 4 or Pentium M. Woodcrest is rumoured to use a 1066 MHz (266 MHz quad-pumped) FSB and have 4 MB of shared L2 cache. Early pictures have shown a dual Socket 480 board, which might be a Woodcrest dev board, but Woodcrest may end up using LGA 771, in order to be backwards-compatible with Dempsey. Woodcrest is said to launch at speeds from 2.5 to 2.93 GHz.
Clovertown
A quad-core version of Woodcrest, consisting of two Woodcrest dies on a multi-chip module. Rumoured to use a 1066 MHz FSB. Intel plans to release Clovertown towards the end of 2006, and the clock speeds will likely be a step or two down from Woodcrest.
Whitefield
A quad-core processor, partially based on Woodcrest, using the new Common System Interface (CSI) bus, which will be shared with the Itanium 2 processors of its generation (beginning with the "Tukwila" core). Whitefield will have 16 MB of L2 cache. Whitefield will originally use a 65 nm process, and it might later switch to a 45 nm process. Whitefield has been reported to be cancelled, and replaced with another processor, codenamed Tigerton. More recent news implies that Whitefield has not been cancelled after all.
Tigerton
A multi-core processor, to be released in place of Whitefield. Tigerton is speculated to be an MP-capable version of Clovertown.
Dunnington
The 45 nm successor to Tigerton (or Whitefield), which is said to be an eight-core processor, but rumours have placed the core count at anywhere from four to thirty-two cores.
Harpertown
Harpertown is said to be a 45 nm, eight-core processor with 12 MB of L2 cache. An older rumour stated that it was simply the 45 nm shrink of Woodcrest, but that has since changed. Note that the most recent description of Harpertown is very similar to the previously leaked information regarding Dunnington.
Gainestown
Quad-core processor based on Intel's upcoming Nehalem microarchitecture. Rumoured to start at 3.0 GHz.
Table of Xeon Processors
Xeon Processors, Designations, and Characteristics | ||||||
---|---|---|---|---|---|---|
Public Desigination | Core (Intel Codename) | CPU Frequency | Frontside Bus Frequency / Theoretical Bandwidth | Cache | Interface | Additional Features |
Pentium II Xeon | Drake | 400 to 450 MHz | 100 MHz / 800 MB/s | 16 KB L1 data + 16 KB L1 instruction; 512 KB/1 MB/2 MB L2 | Slot 2 | N/A |
Pentium III Xeon | Tanner | 500 to 550 MHz | 100 MHz / 800 MB/s | 16 KB L1 data + 16 KB L1 instruction; 512 KB/1 MB/2 MB L2 | Slot 2 | Support of SSE instructions and Processor Serial Number |
Pentium III Xeon | Cascades | 600 to 1000 MHz | 133 MHz / 1066 MB/s | 16 KB L1 data + 16 KB L1 instruction; 256 KB L2 | Slot 2 | On-Die L2 Cache |
Pentium III Xeon | Cascades 2 MB | 700 to 900 MHz | 100 MHz / 800 MB/s | 16 KB L1 data + 16 KB L1 instruction; 2 MB L2 | Slot 2 | Larger L2 cache, and support for more than 2-way configurations |
Xeon | Foster | 1400 to 2000 MHz | 400 MHz / 3.2 GB/s | 8 KB L1 data + 12 K L1 instruction; 256 KB L2 | Socket 603 | Based on Pentium 4's Netburst core; supports SSE2 and removes Processor Serial Number |
Xeon MP | Foster MP | 1400 to 1600 MHz | 400 MHz / 3.2 GB/s | 8 KB L1 data + 12 K L1 instruction; 256 KB L2; 512 KB/1 MB L3 | Socket 603 | Adds L3 cache, and support for more than 2-way configurations, supports Hyper-Threading |
Xeon | Prestonia | 1600 to 3000 MHz | 400 MHz / 3.2 GB/s | 8 KB L1 data + 12 K L1 instruction; 512 KB L2 | Socket 603 | Supports Hyper-Threading, larger L2 cache |
Xeon | Prestonia | 2000 to 3066 MHz | 533 MHz / 4.2 GB/s | 8 KB L1 data + 12 K L1 instruction; 512 KB L2 | Socket 604 | Faster Front-Side Bus |
Xeon | Gallatin | 3066 to 3200 MHz | 533 MHz / 4.2 GB/s | 8 KB L1 data + 12 K L1 instruction; 512 KB L2; 1 MB/2 MB L3 | Socket 604 | Adds L3 cache |
Xeon MP | Gallatin | 1500 to 3000 MHz | 400 MHz / 3.2 GB/s | 8 KB L1 data + 12 K L1 instruction; 512 KB L2; 1 MB/2 MB/4 MB L3 | Socket 603 | Adds L3 cache, and support for more than 2-way configurations |
Xeon | Nocona | 2800 to 3600 MHz | 800 MHz / 6.4 GB/s | 16 KB L1 data + 12 K L1 instruction; 1 MB L2 | Socket 604 | Larger caches; support for SSE3, EM64T (Intel's name for AMD64) |
Xeon | Irwindale | 3000 to 3600 MHz | 800 MHz / 6.4 GB/s | 16 KB L1 data + 12 K L1 instruction; 2 MB L2 | Socket 604 | Larger L2 cache, dynamic speed-variation and the XD (eXecute Disable) bit (Intel's name for the NX bit). |
Xeon MP | Cranford | 3167 to 3667 MHz | 667 MHz / 5.3 GB/s | 16 KB L1 data + 12 K L1 instruction; 1 MB L2 | Socket 604 | Support for 4-way and more configurations. |
Xeon MP | Potomac | 2833 to 3333 MHz | 667 MHz / 5.3 GB/s | 16 KB L1 data + 12 K L1 instruction; 1 MB L2; 4 MB/8 MB L3 | Socket 604 | Adds L3 cache, support for 4-way and more configurations. |
Xeon | Paxville DP | 2800 MHz | 800 MHz / 6.4 GB/s | 16 KB L1 data + 12 K L1 instruction per core; 2 MB L2 per core | Socket 604 | Dual-core processor |
Xeon MP | Paxville | 2667 to 3000 MHz | 667 MHz / 5.3 GB/s | 16 KB L1 data + 12 K L1 instruction per core; 1 MB/2 MB L2 per core | Socket 604 | Dual-core processor, support for 4-way and more configurations. Supports VT with compatible BIOS |
Xeon MP | Paxville | 2800 to 3000 MHz | 800 MHz / 6.4 GB/s | 16 KB L1 data + 12 K L1 instruction per core; 1 MB/2 MB L2 per core | Socket 604 | Faster Front-Side Bus |
See also: List of Intel microprocessors
External links
- Intel Pentium II Xeon technical specifications
- Intel Pentium III Xeon technical specifications [sic]
- Intel Pentium4 Xeon technical specifications
- Intel Pentium II Xeon and Pentium III Xeon images and descriptions at cpu-collection.de