Pentium D

Pentium D. The Pentium D was a series of desktop central processing units introduced by Intel in 2005, representing the company's first mainstream multi-core processors for the consumer market. Based on the NetBurst microarchitecture, it consisted of two separate Pentium 4 cores packaged on a single die or multi-chip module. The launch was a direct competitive response to the emerging multi-core offerings from rival Advanced Micro Devices, specifically the Athlon 64 X2.

Overview

The introduction of the Pentium D marked a significant strategic shift for Intel, moving away from the pursuit of ever-higher clock speeds with the Pentium 4 and towards thread-level parallelism. It was formally announced in the spring of 2005 at the Intel Developer Forum. The processor required new supporting motherboards based on the Intel 945 or Intel 955X chipsets, which utilized the LGA 775 socket. This platform was part of a broader Intel platform initiative that also included the Intel Viiv technology brand for digital home entertainment systems.

Architecture

The initial Pentium D cores, codenamed Smithfield, were essentially two Prescott cores manufactured on a 90-nanometer process and placed on a single die with a shared front-side bus connection to the northbridge. This design lacked an advanced shared CPU cache, with each core possessing its own dedicated L2 cache, leading to potential inefficiencies in inter-core communication. The later Presler core, built on a 65-nanometer process, moved to a multi-chip module design with two separate dies. All Pentium D processors lacked Hyper-Threading technology, a feature present on some contemporary Pentium 4 models, and were strictly dual-core designs.

Models and specifications

The Pentium D family was segmented into several lines. The mainstream 800-series, including models like the 820 and 840, were based on the Smithfield core. The higher-performance 900-series, such as the 920 and 960, utilized the more efficient Presler core and often featured higher clock speeds and front-side bus rates. A budget-oriented line, the Pentium Dual-Core, was later derived from the architecture. Key specifications varied by model but typically ranged from 2.8 GHz to 3.6 GHz in clock speed, with front-side bus speeds of 800 MT/s. Thermal design power was notably high, especially for early models, often exceeding 130 watts, which required robust system cooling.

Performance and reception

Initial critical reception of the Pentium D was mixed. While it provided a tangible performance boost in well-threaded applications like video encoding over single-core Pentium 4 chips, its performance in most general and gaming workloads was often surpassed by the more integrated Athlon 64 X2 from Advanced Micro Devices. Reviewers from publications like AnandTech and Tom's Hardware frequently highlighted its high thermal design power and power consumption as significant drawbacks. The architecture's limitations, particularly its lack of a shared cache and inefficient front-side bus-based communication, became apparent when compared to the subsequent Intel Core 2 microarchitecture, which was based on the more efficient Pentium M design lineage.

Successor and legacy

The Pentium D was succeeded in 2006 by the Intel Core 2 series, built on the new Core microarchitecture, which delivered dramatically better performance and power efficiency. The Pentium D's primary legacy was in accelerating the industry-wide transition to multi-core computing for the mainstream market. It served as a stopgap product for Intel during a period of intense competition with Advanced Micro Devices, maintaining market presence while the company completed development of its more revolutionary Core design. The platform also helped drive adoption of the LGA 775 socket, which would remain in use for several subsequent generations of Intel processors. Category:Intel microprocessors Category:Computer-related introductions in 2005