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Pentium D
Pentium D
Pentium D
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Pentium D
Logo as of 2006
General information
LaunchedMay 25, 2005; 20 years ago (2005-05-25)
DiscontinuedJuly 13, 2010; 15 years ago (2010-07-13)[1]
Marketed byIntel
Designed byIntel
Common manufacturer
  • Intel
CPUID code0F47h (Smithfield)
0F65h (Presler)
Product codeSmithfield: 80551
Presler: 80553
Performance
Max. CPU clock rate2.66 GHz to 3.73 GHz
FSB speeds533 MT/s to 1066 MT/s
Cache
L1 cache32 KB (16 KB (8 KB instructions + 8 KB data) x 2)
L2 cache2–4 MB
Architecture and classification
ApplicationDual-core desktop
Technology node90 nm to 65 nm
MicroarchitectureNetBurst
Instruction setx86-64
InstructionsMMX, SSE, SSE2, SSE3
Extensions
Physical specifications
Transistors
  • Smithfield: 176 million
  • Presler: 376 million
Cores
  • 2 (2×1)
Socket
Products, models, variants
Core names
  • Smithfield
  • Presler
History
Predecessors
Successors
Support status
Unsupported

Pentium D[2] is a range of desktop 64-bit x86-64 processors based on the NetBurst microarchitecture, which is the dual-core variant of the Pentium 4 manufactured by Intel. Each CPU comprised two cores. The brand's first processor, codenamed Smithfield and manufactured on the 90 nm process, was released on May 25, 2005, followed by the 65 nm Presler nine months later.[3] The core implementation on the 90 nm Smithfield and later 65 nm Presler are designed differently but are functionally the same. The 90 nm Smithfield contains a single die, with two adjoined but functionally separate CPU cores cut from the same wafer. The later 65 nm Presler utilized a multi-chip module package, where two discrete dies each containing a single core reside on the CPU substrate. Neither the 90 nm Smithfield nor the 65 nm Presler were capable of direct core to core communication, relying instead on the northbridge link to send information between the two cores.

By 2004, the NetBurst processors reached a clock speed barrier at 3.8 GHz due to a thermal (and power) limit exemplified by the Presler's 130 watt thermal design power[4] (a higher TDP requires additional cooling that can be prohibitively noisy or expensive). The future belonged to more energy efficient and slower clocked dual-core CPUs on a single die instead of two.[5] However, the Pentium D did not offer significant upgrades in design,[6] still resulting in relatively high power consumption.[4]

The final shipment date of the dual die Presler chips was August 8, 2008,[7] which marked the end of the Pentium D brand and also the NetBurst microarchitecture. The Pentium D line was removed from the official price lists on July 13, 2010.

Pentium D/Extreme Edition

[edit]
Pentium D 930 (Presler) with Intel 945GC chipset

The dual-core CPU is capable of running multi-threaded applications typical in transcoding of audio and video, compressing, photo and video editing and rendering, and ray-tracing. Single-threaded applications, including most older games, do not benefit much from a second core compared to an equally clocked single-core CPU. Nevertheless, the dual-core CPU is useful to run both the client and server processes of a game without noticeable lag in either thread, as each instance could be running on a different core. Furthermore, multi-threaded games benefit from dual-core CPUs.

In 2008, many business applications were not optimized for multiple cores. They ran at similar speed when not multitasking on the Pentium D or older Pentium 4 branded CPUs at the same clock speed.[citation needed] However, in multitasking environments such as BSD, Linux, Microsoft Windows operating systems, other processes are often running at the same time; if they require significant CPU time, each core of the Pentium D branded processor can handle different programs, improving overall processing speed over its single-core Pentium 4 counterpart.

Intel Pentium D processor family
Original

logo

2006

logo

Desktop
Code-named Node Date released
Pentium D logo as of 2005 Pentium D logo as of 2006 Smithfield
Presler 		90 nm
65 nm 		May 2005
Jan 2006
Original Pentium Extreme Edition logo Pentium Extreme Edition logo as of 2006 Smithfield XE
Presler XE 		90 nm
65 nm 		May 2005
Jan 2006
List of Intel Pentium D processors

Smithfield

[edit]
Underside of a Pentium D 820

In April 2005, Intel's biggest rival, AMD, had x86 dual-core processors intended for workstations and servers on the market, and was poised to launch a comparable product intended for desktop computers. As a response, Intel developed Smithfield, the first x86 dual-core processor intended for desktop computers, beating AMD's Athlon 64 X2 by a few weeks. Intel first launched Smithfield on April 16, 2005 in the form of the 3.2 GHz Hyper-threading enabled Pentium Extreme Edition 840. On May 26, 2005, Intel launched the mainstream Pentium D branded processor lineup with initial clock speeds of 2.8, 3.0, and 3.2 GHz with model numbers of 820, 830, and 840 respectively. In March 2006, Intel launched the last Smithfield processor, the entry-level Pentium D 805, clocked at 2.66 GHz with a 533 MT/s bus. The relatively cheap 805 was found to be highly overclockable; 3.5 GHz was often possible with good air cooling. Running it at over 4 GHz was possible with water cooling, and at this speed the 805 outperformed the top-of-the-line processors (May 2006) from both major CPU manufacturers (the AMD Athlon 64 FX-60 and Intel Pentium Extreme Edition 965) in many benchmarks including power consumption.[8]

The 805 and 820 models had a 95 watt TDP. All other models were rated at 130 watt.

All Smithfield processors were made of two 90 nm Prescott cores, next to each other on a single die with 1 MB of Level 2 (L2) cache per core. Hyper-threading was disabled in all Pentium D 8xx-series Smithfields with the exception of the Pentium Extreme Edition 840. Smithfield did not support Intel VT-x—Intel's x86 virtualization (formerly Vanderpool).

All Pentium D processors supported Intel 64 (formerly EM64T), XD Bit, and were manufactured for the LGA 775 form factor. The only motherboards guaranteed to work with the Pentium D (and Extreme Edition) branded CPUs were those based on the 945-, 955-, 965- and 975-series Intel chipsets, as well as the nForce 4 SLI Intel Edition and ATI Radeon Xpress. The Pentium D 820 did not work with the nForce 4 SLI Intel Edition chipset due to some power design issues, though they were rectified in the X16 version. The 915- and 925-series chipsets did not work at all with the Smithfields, as they did not support more than one core (to prevent manufacturers making a cheap dual CPU motherboard capable of supporting Xeon CPUs, as had happened with the 875P chipset). The 865- and 875-series chipsets supported multiprocessing. Motherboards with them might be Pentium D compatible with an updated BIOS.

A week after its launch, Intel officially denied a report[9] in Computerworld Today Australia that the Pentium D branded CPUs included "secret" digital rights management features in their hardware that could be utilized by Microsoft Windows and other operating systems, but was not publicly disclosed. While Intel admitted that there were some DRM technologies in the 945- and 955-series chipsets, it stated that the extent of the technologies was exaggerated, and that the technologies in question had been present in Intel's chipsets since the 875P.

Smithfield XE

[edit]

The Pentium Extreme Edition (PXE) was introduced at the Spring 2005 Intel Developers Forum, not to be confused with the "Pentium 4 Extreme Edition" (an earlier, single-core processor occupying the same niche). The processor was based on the dual-core Pentium D branded Smithfield, but with Hyper-threading enabled, thus any operating system saw four logical processors. It also had an unlocked multiplier to allow for easier overclocking. It was initially released as Intel Pentium Extreme Edition 840 at 3.20 GHz, in early 2005, at a price point of $999.99 (OEM price) or $1,200 (retail). The only chipsets that worked with the Extreme Edition 840 were Intel's 955X, NVIDIA's nForce4 SLI Intel Edition, and ATi Radeon Xpress 200. Using a Pentium Extreme Edition branded CPU with an Intel 945-series chipset will disable Hyper-threading.

Presler

[edit]
Intel Pentium D 930 3.00GHz on an Intel D945GCCR motherboard

The last generation of Pentium D branded processors was Presler released on January 16, 2006, identified by the product code 80553, and made of two 65 nm process cores found also in Pentium 4 branded Cedar Mill CPUs. Presler introduced the multi-chip module, or MCM, which consisted of two single-core dies placed next to each other on the same substrate package. This allowed Intel to produce these processors at a reduced production cost as a result of higher yields. Presler was supported by the same chipsets as Smithfield. It was produced using 65 nm technology similar to Yonah. Presler communicated with the system using an 800 MT/s FSB, and its two cores communicated also using the FSB, just as in Smithfield. Presler also included Intel VT-x (formerly Vanderpool) – although this was limited to the 9x0 models, and not in the 9x5 models– Intel 64, XD bit, and Enhanced Intel SpeedStep Technology (EIST). Presler was released in the first quarter of 2006 with a 2×2 MB Level 2 cache. Its models included 915, 920, 925, 930, 935, 940, 945, 950 and 960 (with a respective 2.8, 2.8, 3.0, 3,0, 3.2, 3.2, 3.4, 3.4, and 3.6 GHz clock frequency).

All steppings of Presler models 915, 920, 925, 930, and 935, as well as the C1, D0 steppings of 940, 945 featured a 95 watt TDP. All other models (i.e. certain models with 3.2 GHz or faster clock frequencies) were rated at 130 watt — a 37% increase in power consumption.[10]

[*] The first batch of Presler processors (revision B1) had the EIST feature turned off by a microcode update because of stability issues. That affected only its power consumption, when idle, and thermal dissipation. Chips with working EIST started shipping in Q2 2006. They had a different S-Spec number which can be found in Intel errata documentation.

Presler XE

[edit]

The Pentium Extreme Edition based on the dual-core Pentium D branded Presler was introduced as the 955 model, at 3.46 GHz, and used a 1066 MT/s FSB compared to the 800 MT/s in the non-Extreme edition. A second version, the 965 at 3.73 GHz followed in March 2006. Both CPUs also feature Hyper-Threading Technology and an unlocked multiplier. Overclockers have been able to overclock the core to 4.26 GHz using air cooling simply by raising the unlocked CPU multiplier.

The Presler Extreme Edition was intended to only be combined with the Intel 975X chipset, it could also work with the 955X chipset, though this combination was not supported by Intel. The i975X featured the ICH7R southbridge and supported all LGA 775 (Socket T) Pentium 4, Pentium D, and Pentium Extreme Edition branded processors.

Successor

[edit]
Main article: Intel Core 2

The Pentium D brand was merged with the Pentium 4 brand and succeeded on July 27, 2006, by the Core 2 branded line of processors with the Core microarchitecture released as dual- and quad-core processors branded Duo, Quad, and Extreme.

Implementation

[edit]

In a single-processor scenario, the CPU-to-northbridge link is point-to-point and the only real requirement is that it is fast enough to keep the CPU fed with data from memory.

When assessing the Pentium D, it is important to note that it is essentially two CPUs in the same package and that it will face the same bus contention issues as a pair of Xeons prior to the Dual Independent Bus architecture introduced with the Dual-Core Dempsey Xeons. To use a crude analogy one could say that instead of using a single cable between CPU and north bridge, one must use a Y-splitter. Leaving aside advanced issues such as cache coherency, each core can only use half of the 800 MT/s FSB bandwidth when under heavy load.

Comparison to Athlon 64 X2

[edit]

The competing AMD Athlon 64 X2, although running at lower clock rates and lacking hyper-threading, had some significant advantages over the Pentium D, such as an integrated memory controller, a high-speed HyperTransport bus, a shorter pipeline (12 stages compared to the Pentium D's 31), and better floating point performance,[11] more than offsetting the difference in raw clock speed. Also, while the Athlon 64 X2 inherited mature multi-core control logic from the multi-core Opteron, the Pentium D was seemingly rushed to production and essentially consisted of two CPUs in the same package. Indeed, shortly after the launch of the mainstream Pentium D branded processors (26 May 2005) and the Athlon 64 X2 (31 May 2005), a consensus arose that AMD's implementation of multi-core was superior to that of the Pentium D.[12][13] As a result of this and other factors, AMD surpassed Intel in desktop PC sales at US retail stores for a period of time, although Intel retained overall market leadership because of its exclusive relationships with direct sellers such as Dell.[14]

Comparison to Pentium Dual-Core

[edit]

In 2007, Intel released a new line of desktop processors under the brand Pentium Dual Core, using the Core microarchitecture (which was based upon the Pentium M architecture, which was itself based upon the Pentium III Tualatin). The newer Pentium Dual-Core processors give off considerably less heat (65 watt max) than the Pentium D (95 or 130 watt max). They also run at lower clock rates, only have up to 2 MB L2 Cache memory while the Pentium D has up to 2×2 MB, and they lack Hyper-threading.

The Pentium Dual-Core has a wider execution unit (four issues wide compared to the Pentium D's three) and its 14 stages-long pipeline is less than half the length of the Pentium D's, allowing it to outperform the Pentium D in most applications despite having lower clock speeds and less L2 cache memory.

See also

[edit]

References

[edit]
[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia

Pentium D

View on Grokipedia
from Grokipedia
The Pentium D is a family of dual-core desktop microprocessors developed by Corporation, introduced on May 26, 2005, as the mainstream successor to the single-core processors and based on the microarchitecture. All models support Intel 64-bit extensions. The initial models, codenamed Smithfield and manufactured on a , featured two independent cores sharing a single die with 1 MB L2 cache per core, clock speeds starting at 2.66 GHz for the Pentium D 805, a of 533–800 MHz, and TDP ratings of 95 or 130 depending on the model, all compatible with the socket. Subsequent Presler-based models, produced on a starting in 2006, offered higher clock speeds up to 3.6 GHz (as in the Pentium D 960), increased cache options up to 4 MB total L2, and TDP ratings ranging from 95 to 130 , while maintaining compatibility with motherboards and introducing minor enhancements like improved Execute Disable Bit protection. Designed primarily for multitasking in home and business desktops, the Pentium D series provided better parallel processing capabilities than prior single-core offerings but was criticized for high power consumption and heat output due to the aging design, leading Intel to phase it out in favor of the more efficient Core 2 Duo architecture by late 2006.

Overview

History and Development

The Pentium D represented Intel's entry into dual-core desktop processing, launched on May 26, 2005, as a direct response to AMD's , which had debuted in April 2005 and pressured Intel's single-core dominance in the consumer market. Developed amid intensifying competition from , the processor marked a strategic pivot from the high-clock-speed focus of the single-core , which had reached performance and power efficiency limits under the . The initial design, codenamed Smithfield and fabricated on a , was first publicly confirmed by in December 2004, building on the architecture to combine two single-core dies into a for improved multitasking in desktop applications. Positioned as 's mainstream dual-core brand for desktops, it targeted the socket to leverage existing compatibility and appeal to gamers, content creators, and general users seeking better parallel processing without a full platform overhaul. Subsequent updates followed quickly, with the Presler core—shrunk to 65 nm for better efficiency—launching in January 2006 to refine the dual-core formula and extend the lineup's competitiveness. Production of the Pentium D brand wound down as Intel transitioned to the Core microarchitecture, with the final shipment of Presler-based models occurring on August 8, 2008, effectively ending the NetBurst era in consumer desktops.

Key Specifications

The Pentium D processors feature a dual-core design based on the microarchitecture, providing two independent processing cores within a single package to enable parallel task execution. Each core supports the instruction set through Intel's EM64T technology, allowing for capabilities essential for handling larger memory addressing and enhanced application performance. These processors utilize the socket, compatible with a range of 900-series chipsets, and employ a (FSB) operating at speeds of 533 MT/s or 800 MT/s to facilitate data transfer between the CPU, , and other components. Power consumption varies by model, with (TDP) ratings spanning 95 W to 130 W, reflecting differences in core complexity and fabrication processes while necessitating robust cooling solutions for sustained operation. The Smithfield variants are fabricated on a with approximately 230 million transistors, whereas the subsequent Presler variants use a featuring around 376 million transistors, enabling improved power efficiency and density. The instruction set includes foundational extensions such as MMX for processing, SSE and SSE2 for single-instruction multiple-data operations, and SSE3 for enhanced streaming SIMD, but lacks later extensions like SSSE3; notably, these processors do not include integrated graphics, relying on discrete GPU solutions for visual output. This dual-core implementation operates without dedicated on-die inter-core communication pathways, relying instead on the shared FSB for coordination.
SpecificationDetails
Core Count2 (dual-core)
Architecture Supportx86-64 (EM64T)
SocketLGA 775
Front-Side Bus (FSB)533–800 MT/s
TDP Range95–130 W
Manufacturing Process90 nm (Smithfield), 65 nm (Presler)
Transistor Count~230 million (90 nm), ~376 million (65 nm)
Key Instruction SetsMMX, SSE, SSE2, SSE3 (no SSSE3 or later)
Integrated GraphicsNone

Core Architectures

Smithfield Core

The Smithfield core represented Intel's initial foray into dual-core desktop processing for the Pentium D series, employing a single-die architecture built on the 90 nm process node. This design integrated two independent Prescott-derived cores on one chip, each with its own dedicated 16 KB L1 instruction cache, 16 KB L1 data cache, and 1 MB of L2 cache, resulting in a total of 2 MB L2 cache across the processor. The cores operated on the NetBurst microarchitecture and shared a front-side bus of 533–800 MHz, with support for Hyper-Threading disabled to emphasize multi-core parallelism over single-threaded performance. Fabricated with approximately 230 million transistors, the Smithfield core was packaged in a 775-land Flip-Chip Land Grid Array (FC-LGA) for Socket 775 compatibility. The model lineup for the 800-series Pentium D processors based on the Smithfield core included four variants, launched in May 2005. The entry-level Pentium D 805 operated at 2.66 GHz with a 533 MHz and a locked multiplier of 20x, while the Pentium D 820 ran at 2.8 GHz on an 800 MHz bus with a 14x multiplier. Stepping up, the Pentium D 830 achieved 3.0 GHz with a 15x multiplier, and the top-end Pentium D 840 reached 3.2 GHz using a 16x multiplier. Notably, the Pentium D 805 was the only model in the series with an unlocked multiplier, enabling easier for enthusiasts. Initial recommended pricing started at $163 for the 805, $241 for the 820, $316 for the 830, and $530 for the 840. Power and thermal characteristics varied by model to balance performance and efficiency on the 90 nm node. The lower-speed Pentium D 805 and 820 had a (TDP) of 95 W, with core voltages ranging from 1.200 to 1.400 V and maximum case temperatures up to 67.5°C under load. In contrast, the higher-clocked Pentium D 830 and 840 consumed 130 W TDP, with similar voltage ranges but elevated maximum case temperatures of around 72°C, necessitating robust cooling solutions for sustained operation. These specifications reflected the challenges of integrating dual cores on a single die, including higher power density compared to single-core predecessors.

Presler Core

The Presler core marked a key evolution in Intel's Pentium D lineup, transitioning to a 65 nm fabrication process that enhanced power efficiency and density over the prior 90 nm Smithfield design. It adopted a (MCM) architecture, featuring two discrete dies mounted on a single substrate, with each die containing one processing core and an exclusive 2 MB Advanced Transfer Cache (L2) per core, yielding 4 MB of total L2 cache (2 MB per core). This separation allowed for better and thermal management in dual-core operation, while maintaining the microarchitecture's 20-stage pipeline. Launched as the Pentium D 900 series in January 2006, Presler-based models spanned clock speeds from 2.8 GHz to 3.6 GHz, exemplified by the entry-level Pentium D 915 at 2.8 GHz with 800 MT/s (FSB) and the higher-end Pentium D 945 at 3.4 GHz. (TDP) ranged from 95 W for standard models like the 915 and 945 to 130 W in select higher-performance variants, supported by a total transistor count of 376 million across both dies. Following a Q2 stepping update, the series gained full support for Enhanced SpeedStep Technology (EIST) to enable dynamic voltage and . Production of Presler-core Pentium D processors ended with final shipments on August 8, 2008, paving the way for Intel's shift to 2 architecture.

Extreme Edition Variants

Smithfield XE

The Pentium D Extreme Edition 840, launched on April 18, , represented Intel's initial foray into high-end dual-core processors with enhanced threading capabilities. This model operated at a clock speed of 3.2 GHz and was designed specifically for performance enthusiasts seeking superior multitasking in desktop applications. Key enhancements in the Extreme Edition 840 included the enablement of Hyper-Threading Technology (HTT), allowing the dual-core processor to handle up to four threads simultaneously for improved parallel processing efficiency. It featured 1 MB L2 cache per core (totaling 2 MB), an 800 MHz , and a (TDP) of 130 W. Additionally, the processor incorporated an unlocked multiplier, enabling users to overclock beyond the stock 16x ratio for further performance gains. Priced at an initial MSRP of $999, the Pentium D Extreme Edition 840 targeted enthusiast builders and gamers, positioning it as a premium option in Intel's early dual-core lineup compatible with the LGA 775 socket and 90 nm manufacturing process. The die integration mirrored the standard Smithfield design on a single 90 nm silicon die, but with these unlocked and threading features to differentiate it for high-performance computing.

Presler XE

The Pentium D Extreme Edition processors based on the Presler core represented Intel's high-end dual-core offerings in early 2006, targeted at enthusiasts and gamers seeking maximum performance from the architecture. The lineup included the model 955, launched on December 27, 2005, operating at 3.46 GHz across both cores, and the model 965, released on March 26, 2006, with both cores clocked at 3.73 GHz. These processors utilized a design, similar to the standard Presler core, but were optimized for extreme workloads through the inclusion of Technology, enabling four logical threads. Key enhancements in the Presler XE variants focused on improved efficiency and capability for high-performance applications. Each core featured 2 MB of dedicated L2 cache, totaling 4 MB on the die, paired with a for enhanced data throughput. Fabricated on a , these chips maintained a of 130 W, offering better thermal headroom compared to the preceding 90 nm Smithfield XE due to the shrink, which allowed for higher clock speeds without proportional power increases. further boosted multithreaded performance in gaming and content creation scenarios. Priced at an MSRP of $999 for the 955 and ranging up to $1,199 retail for the 965, these models were positioned as Intel's desktop processors immediately prior to the introduction of the Core 2 Duo Extreme Edition in mid-2006. Their unlocked multipliers facilitated straightforward , appealing to users pushing boundaries in gaming rigs, with the 65 nm design providing additional headroom for sustained boosts beyond stock speeds.

Technical Implementation

Microarchitecture Details

The Pentium D processors utilize Intel's , adapted for dual-core operation by pairing two independent Prescott-derived cores on a single die or . These cores retain the characteristic 31-stage of the Prescott design, optimized for high clock frequencies but resulting in significant misprediction penalties. Unlike later multi-core architectures, there is no direct inter-core communication pathway; the cores instead exchange data through the system's northbridge chipset via the shared (FSB), which introduces latency in coordinated workloads. Each core features two integer execution units, with the simple integer ALUs double-pumped to operate at twice the core clock speed for basic arithmetic, alongside a dedicated floating-point multiplier unit. Branch prediction sees enhancements over prior single-core variants, employing a two-level adaptive predictor with a 16-bit global history register and a 4096-entry Branch Target Buffer (BTB), enabling zero-bubble recovery on correct predictions. These adaptations aim to mitigate the pipeline's depth-related inefficiencies while maintaining compatibility with the x86 instruction set. The architecture supports the full instruction set and extensions, including 13 new instructions for enhanced multimedia processing, but lacks support (Intel VT-x), which is only available in select Presler models such as the Pentium D 920, 930, and 940, and lacks advanced for fine-grained core-level . The shared FSB, operating at speeds up to 800 MHz, creates notable contention in multi-threaded scenarios, where bandwidth can drop by up to 14% under heavy parallel loads as both cores vie for memory access. Thermal design remains a challenge, with the extended and aggressive clock scaling contributing to elevated heat output and poor efficiency in dual-core scaling; ratings range from 95 W for lower-clocked models to 130 W for higher-end variants, necessitating robust cooling solutions to prevent throttling.

Cache and Bus

The Pentium D processors employ a dual-level tailored to their NetBurst-based dual-core , with no shared higher-level cache beyond the cores. Each core features a split L1 cache consisting of a 16 KB data cache and a 12 KB micro-operation trace cache for instructions, providing a total of 28 KB of L1 cache per core to support rapid access for execution units. The L2 cache is unified and exclusive to each core, varying by model: Smithfield variants include 1 MB per core for a total of 2 MB, while Presler variants expand this to 2 MB per core for a total of 4 MB, all operating at full core clock speed to minimize latency for frequently accessed data. This per-core L2 configuration ensures independent caching but lacks a shared L3 cache, meaning inter-core data sharing relies on the , potentially introducing overhead in multi-threaded workloads. Memory support in the Pentium D is handled externally, as the processors lack an integrated and depend on the motherboard's northbridge for RAM interfacing. Early models, paired with chipsets like the 915, support dual-channel DDR1 up to 4 GB, while later variants with chipsets such as the 965 enable dual-channel DDR2 support up to 8 GB, offering bandwidth improvements over single-channel setups without exceeding the era's practical limits for 32-bit or early 64-bit systems. This external architecture allows flexibility in configuration but ties to capabilities, with DDR2 providing higher densities and speeds up to 667 MHz in supported platforms. The Front Side Bus (FSB) serves as the primary interconnect for the Pentium D, linking the dual cores to the memory controller, I/O devices, and other system components in a shared topology. Operating as a quad-pumped bus—transferring data on both rising and falling edges of the clock, effectively quadrupling the base rate—it supports speeds from 533 MT/s to 800 MT/s (corresponding to base clocks of 133 MHz to 200 MHz), with higher rates available on later models to boost overall system throughput. However, the single shared FSB creates contention in dual-core operation, as both cores compete for bandwidth during simultaneous memory accesses, which can bottleneck performance in memory-intensive tasks compared to architectures with dedicated or point-to-point links. This design choice, inherited from the NetBurst family, prioritizes compatibility with existing platforms but highlights limitations in scalable multi-core efficiency.

Performance Comparisons

Versus AMD Athlon 64 X2

The Pentium D and represented the first major dual-core processors for desktop computing, with key architectural differences shaping their competitive dynamics. The Pentium D, built on Intel's , relied on an external integrated into the , which introduced latency in access compared to AMD's approach. In contrast, the utilized the K8 with an on-die integrated , enabling direct DDR access and lower latency for bandwidth-intensive tasks. Additionally, the featured a shorter 12-stage , allowing for quicker instruction execution and better efficiency in branch-heavy workloads, while the Pentium D's deeper pipeline—derived from the Prescott core—prioritized higher clock speeds but suffered from increased branch misprediction penalties. Both processors launched in close proximity in mid-2005, with the Pentium D 820 debuting on May 26 and the following on May 31, positioning them as direct rivals in the emerging dual-core market. Despite the similar timing, AMD quickly established an early lead through favorable benchmark results, as the 's design leveraged existing motherboards with updates, offering easier upgrades over Intel's requirement for new platforms supporting DDR2 memory. In performance, the generally excelled in multi-threaded applications following its launch, benefiting from its integrated and efficient core design, which provided up to 20-30% better throughput in tasks like video encoding and compression compared to equivalent Pentium D models. The Pentium D, however, held advantages in some single-threaded scenarios due to its higher achievable clock speeds, such as the 3.2 GHz Pentium D 840 outperforming lower-clocked Athlon variants in lightly threaded . Overall, independent tests showed the superior in a majority of dual-core optimized workloads, including rendering and simulation. Power efficiency favored the , with ratings ranging from 89 W for entry-level Manchester-core models like the 3800+ to 110 W for higher-end Toledo variants, compared to the 's 95-130 W span. This resulted in lower system-level power draw for setups—typically 125-190 W under load versus the 's 200-310 W—making the more suitable for cooler operation without aggressive cooling solutions. A representative example is the 3800+ (2.0 GHz), which outperformed the Pentium D 820 (2.8 GHz) in gaming benchmarks like and productivity suites such as compression by 10-25%, despite the Intel model's higher clock and larger per-core cache, highlighting AMD's architectural edge in balanced workloads.

Versus Pentium Dual-Core

The processors represented Intel's transition away from the microarchitecture used in the Pentium D toward the newer Core microarchitecture, with desktop models based on the Conroe or Allendale cores. This shift addressed key limitations of NetBurst, such as its deep , by adopting a more balanced design that prioritized efficiency over raw clock speeds. Launched in 2007 as a budget-oriented dual-core option, the series effectively replaced the Pentium D in Intel's value segment, phasing out the older branding for mainstream dual-core computing. In terms of power efficiency, the models had a (TDP) of 65 W, significantly lower than the Pentium D's range of 95–130 W depending on the core variant. This improvement stemmed from the Core microarchitecture's enhanced instructions per clock (IPC), which allowed for superior performance at similar clock speeds without the excessive heat and power draw of . The omitted Hyper-Threading Technology (HTT), as did the mainstream Pentium D models, to maintain its entry-level positioning, but it incorporated advanced power management capabilities like dynamic frequency scaling for better energy utilization. Performance-wise, the outperformed the Pentium D in multi-threaded workloads despite comparable clock rates, largely due to the shorter pipeline and wider execution resources in design, which reduced branch misprediction penalties and improved throughput. For instance, benchmarks from the era showed Core-based dual-cores delivering up to 30% higher IPC in general computing tasks compared to equivalents. This efficiency made the a more viable option for everyday multitasking and emerging multi-threaded applications, solidifying its role as the value successor that diminished the Pentium D's relevance in Intel's lineup.

Legacy and Successors

Successor Processors

The Pentium D processors were directly succeeded by Intel's Core 2 Duo family, launched on July 27, 2006, which introduced the Core microarchitecture—a significant departure from the architecture used in Pentium D—and was manufactured on a node for improved efficiency and performance. This shift marked the end of the era, with the Core 2 Duo providing a unified dual-core design that addressed the multi-chip limitations of earlier Pentium D models like Smithfield. The transition timeline saw Pentium D production rapidly declining after the Core 2 Duo's debut, with Intel ceasing orders for most Pentium D variants by March 2007 and final shipments of the last Presler-based models occurring on August 8, 2008. By 2007, Core 2 had become 's mainstream dual-core platform, effectively phasing out Pentium D from new systems. In terms of branding evolution, the Core 2 Duo targeted mainstream consumers, while the Core 2 Extreme series replaced the high-end Pentium Extreme Edition processors, offering unlocked multipliers and higher clock speeds for enthusiasts. The introduction of Core 2 processors had a substantial market impact, enabling to regain its performance leadership over through superior power efficiency and IPC gains, ending AMD's brief dominance in the dual-core segment during the period. Support for Pentium D effectively concluded around 2010, coinciding with the broader end of compatibility and driver updates for legacy platforms, though Core 2 maintained with existing motherboards. The line, based on a scaled-down , emerged as a budget-oriented successor for entry-level systems.

Known Issues and Criticisms

The Pentium D processors, particularly higher-end models, featured a (TDP) of up to 130 W, which contributed to significant overheating risks under load and necessitated robust cooling solutions such as high-performance air coolers or liquid cooling s. This high power draw was criticized for inefficiency compared to contemporary Athlon 64 X2 processors, which achieved similar or better at lower TDPs around 65–110 W, leading to higher costs and greater heat output. The heat generation scaled rapidly with clock speeds, often resulting in thermal throttling or instability in inadequately cooled setups. Several errata affected the reliability of Pentium D models. In the Smithfield-based 800 series (90 nm dual-die design), issues included potential system hangs from stalls at high core-to-bus ratios and continuous bus lock loops that could prevent resource access between cores. For the Presler-based 900 series (65 nm single-die), early steppings suffered from Enhanced Intel SpeedStep Technology (EIST) instability, where voltage and frequency transitions during Enhanced HALT states could cause system hangs due to improper bus-not-ready (BNR) signaling; this was mitigated via BIOS workarounds rather than a hardware fix. These errata, documented in 's specification updates, highlighted design limitations in and inter-core communication. Performance critiques centered on the lack of architectural advancements over the single-core , with no significant improvements in instructions per clock (IPC) despite the dual-core configuration. The shared (FSB) design led to contention between cores, as both had to route communications externally through the northbridge, reducing and efficiency in multi-threaded workloads compared to AMD's on-die interconnect. This bottleneck diminished the expected dual-core benefits, particularly in latency-sensitive tasks, making the Pentium D feel like a incremental rather than revolutionary upgrade. Contemporary reviews from 2005–2006 offered mixed reception, often portraying the Pentium D as a stopgap measure to introduce dual-core processing while Intel transitioned away from the architecture. While praised for multitasking gains in office and content-creation applications, it was frequently outpaced by AMD's in gaming and overall , with critics noting its high power demands undermined its value. Business-oriented benchmarks showed modest advantages in suites, but these were overshadowed by the processor's and shortcomings. Overclocking stability was limited in Smithfield models due to their dual-die and heat sensitivity, often resulting in inconsistent performance gains or crashes without extensive cooling modifications, whereas Presler models offered better headroom but still required careful voltage management to avoid exacerbating errata-related hangs.

References

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