Pentium D

Lore & Background

The Pentium D was developed as a response to AMD's x86 dual-core processors for workstations and servers, which were on the market by April 2005. Intel launched the first x86 dual-core processor intended for desktop computers, the Smithfield-based Pentium Extreme Edition 840, on April 16, 2005, beating AMD's Athlon 64 X2 by a few weeks. The mainstream Pentium D lineup followed on May 26, 2005, with initial clock speeds of 2.8, 3.0, and 3.2 GHz (models 820, 830, and 840). The last Smithfield processor, the entry-level Pentium D 805 clocked at 2.66 GHz, was launched in March 2006 and was found to be highly overclockable.

Smithfield processors consisted of two 90 nm Prescott cores on a single die with 1 MB of L2 cache per core. Hyper-threading was disabled in all Pentium D 8xx-series Smithfields except the Pentium Extreme Edition 840. The later Presler generation, released on January 16, 2006, used a multi-chip module package with two discrete 65 nm dies on the same substrate, reducing production costs. Neither Smithfield nor Presler supported direct core-to-core communication; they relied on the northbridge link or the front-side bus to exchange information between cores.

By 2004, NetBurst processors had reached a clock speed barrier at 3.8 GHz due to thermal and power limits, exemplified by the Presler's 130 watt TDP. The Pentium D line was removed from official price lists on July 13, 2010, the same day support for Windows 2000 and Windows XP SP2 ended.

Reader's Guide

The Pentium D's significance lies in being Intel's first dual-core desktop processor, enabling multi-threaded applications such as audio/video transcoding, compression, photo and video editing, rendering, and ray-tracing to run more efficiently. Single-threaded applications, including most older games, did not benefit much from a second core compared to an equally clocked single-core CPU, but dual-core CPUs were useful for running both client and server processes of a game without noticeable lag. In multitasking environments like BSD, Linux, and Microsoft Windows, the Pentium D could handle different programs on each core, improving overall processing speed over its single-core Pentium 4 counterpart.

However, the Pentium D did not offer significant design upgrades, still resulting in relatively high power consumption. The future belonged to more energy-efficient and slower-clocked dual-core CPUs on a single die. The final shipment date of the dual-die Presler chips was August 8, 2008, marking the end of the Pentium D brand and the NetBurst microarchitecture. The line's legacy is as a transitional product that brought dual-core computing to the desktop market but was ultimately limited by its thermal and power constraints.

Did You Know?

• The Pentium D 805 was found to be highly overclockable; 3.5 GHz was often possible with good air cooling, and over 4 GHz was possible with water cooling.
• The Pentium Extreme Edition 840 had Hyper-threading enabled, allowing the operating system to see four logical processors.
• Presler processors used a multi-chip module package with two discrete dies, allowing Intel to produce them at reduced cost due to higher yields.