Pentium 4Prescott

On February 1, 2004, Intel introduced a new core codenamed "Prescott". The core used the 90 nm process for the first time, which one analyst described as "a major reworking of the Pentium 4's microarchitecture—major enough that I am surprised Intel did not opt to call this processor the Pentium 5." Despite this overhaul, the performance gains were inconsistent. Some programs benefited from Prescott's doubled cache and SSE3 instructions, whereas others were negatively impacted by its longer pipeline. The Prescott's microarchitecture allowed Prescott to be clocked at slightly higher rates, but not nearly as high as Intel had anticipated. The fastest mass-produced Prescott-based Pentium 4s were clocked at 3.8 GHz. While Northwood ultimately achieved clock speeds 70% higher than Willamette, Prescott ultimately scaled just 12% beyond Northwood, which was attributed to the high power consumption and heat output of the processor. In actual fact Prescott's power and heat characteristics were only slightly higher than those of Northwood of the same speed and near-equal to the Gallatin-based Extreme Editions, but since those processors had already been operating near the limits of what was considered thermally acceptable, this still posed a major issue.

The "Prescott" Pentium 4 contains 125 million transistors and has a die area of 122 mm2. It was fabricated in a 90 nm process with seven levels of copper interconnect. The process has features such as strained silicon transistors and Low-K carbon-doped silicon oxide (CDO) dielectric, which is also known as organosilicate glass (OSG). The Prescott was first fabricated at the D1C development fab and was later moved to F11X production fab.

Originally, two Prescott lines were released: the E-series, with an 800 MT/s FSB and Hyper-Threading support, and the low-end A-series, with a 533 MT/s FSB and Hyper-Threading disabled. Intel eventually added XD Bit (eXecute Disable) and Intel 64 functionality to Prescott.

LGA 775 Prescott uses a rating system, labeling them as the 5xx series (Celeron Ds are the 3xx series, while Pentium Ms are the 7xx series). The LGA 775 version of the E-series uses model numbers 5x0 (520-560), and the LGA 775 version of the A-series uses model numbers 5x5 and 5x9 (505-519). The fastest, the 570J and 571, is clocked at 3.8 GHz. Plans to mass-produce a 4 GHz Pentium 4 were cancelled by Intel in favor of dual core processors, although some European retailers claimed to be selling a Pentium 4 580, clocked at 4 GHz.

The 5x0J series (and its low-end equivalent, the 5x5J and 5x9J series) introduced the XD Bit (eXecute Disable) or Execute Disabled Bit [1] to Intel's line of processors. This technology, introduced to the x86 line by AMD and called NX (No eXecute), can help prevent certain types of malicious code from exploiting a buffer overflow to get executed. Intel also released a series of Prescott supporting Intel 64, Intel's implementation of the AMD-developed x86-64 64-bit extensions to the x86 architecture. These were originally released as the F-series, and only sold to OEMs, but they were later renamed to the 5x1 series and sold to the general public. Two low-end Intel64-enabled Prescotts, based on the 5x5/5x9 series, were also released with model numbers 506 and 516. 5x0, 5x0J, and 5x1 series Prescott incorporates Hyper-Threading in order to speed up some processes that use multithreaded software, such as video editing. The 5x1 series also supports 64 bit computing