Gecko's CPU Library

Intel Pentium 4 Extreme Edition (Gallatin) processors

Introduction: September 2003


The Pentium 4 brand refered to Intel's line of single-core mainstream desktop and laptop central processing units (CPUs) introduced on November 20, 2000 (August 8, 2008 was the date of last shipments of Pentium 4s). They had the 7th-generation architecture, called NetBurst, which was the company's first all-new design since 1995, when the Intel P6 architecture of the Pentium Pro CPUs had been introduced. NetBurst differed from the preceding Intel P6 - of Pentium III, II, etc. - by featuring a very deep instruction pipeline to achieve very high clock speeds (up to 4GHz) limited only by max. power consumption (TDP) reaching up to 115W in 3.6–3.8GHz Prescotts and Prescotts 2M (a high TDP required an additional cooling that was noisy or expensive). In 2004, the initial 32-bit x86 instruction set of the Pentium 4 microprocessors was extended by the 64-bit x86-64 set.

Pentium 4 CPUs introduced the SSE2 and SSE3 instruction sets to accelerate calculations, transactions, media processing, 3D graphics, and games. They also integrated Hyper-threading (HT), a feature to make one physical CPU work as two logical and virtual CPUs. The Intel's flagship Pentium 4 also came in a low-end version branded Celeron (often referred to as Celeron 4), and a high-end derivative, Xeon, intended for multiprocessor servers and workstations.

The Pentium 4 had an IHS (Integrated Heat Spreader) that prevented the CPU core from accidentally getting damaged when mounting and unmounting cooling solutions. Prior to the IHS, a CPU shim was sometimes used by people worried about damaging the core. Overclockers sometimes removed the IHS on Socket 478 chips to allow for more direct heat transfer. However, on LGA775 chips the IHS was directly welded to the processor core, meaning that the IHS cannot be removed without irreparably damaging the processor.

In 2005, the Pentium 4 was superseded by the Pentium D and Pentium Extreme Edition dual-core CPUs.

The Gallatin core

In September 2003, at the Intel Developer Forum, the Pentium 4 Extreme Edition (P4EE) was announced, just over a week before the launch of Athlon 64, and Athlon 64 FX (AMD64 FX). The design was mostly identical to Pentium 4 (to the extent that it would run in the same motherboards), but differed by an added 2MB of Level 3 cache. It shared the same Gallatin core as the Xeon MP, though in a Socket 478 form factor (as opposed to Socket 603 for the Xeon MP) and with an 800MT/s bus, twice as fast as that of the Xeon MP. An LGA 775 version was also available.

While Intel maintained that the Extreme Edition was aimed at gamers, some viewed it as an attempt to steal the Athlon 64's launch thunder, nicknaming it the "Emergency Edition". With a price tag of ~$1000, it was also referred to as the "Expensive Edition" or "Extremely Expensive". Many condemned Intel for cannibalizing the Xeon line, but no such complaints were aimed at AMD's Athlon 64 FX-51, which was merely a repackaged Opteron 148.

The effect of the added cache was somewhat variable. In office applications, the Extreme Edition was generally a bit slower than the Northwood, owing to higher latency added by the L3 cache. Some games benefited from the added cache, particularly those based on the Quake III and Unreal engines. However, the area which improved the most was multimedia encoding, which was not only faster than the Pentium 4, but also on both Athlon 64s.

A slight performance increase was achieved in late 2004 by increasing the bus speed from 800MT/s to 1066MT/s. Only one Gallatin-based chip at 3.46GHz was released before the Extreme Edition was migrated to the Prescott core. The new 3.73GHz Extreme Edition had the same features as a 6x0-sequence Prescott-2M, but with a 1066MT/s bus. In practice however, the 3.73GHz Extreme Edition almost always proved to be slower than the 3.46GHz version.

The "Pentium 4 Extreme Edition" should not be confused with a similarly-named later model, the "Pentium Extreme Edition", which is based on the dual-core Pentium D.

Source: Wikipedia, the free encyclopedia.