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Inside the Pentium D 805

A 4.1 GHz Dual Core at $130 - Can it be True?
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The Pentium D 805 is based on the first Intel dual core processor, the Pentium D with the Smithfield core. Its predecessors in this family were rated at clock speeds of 2.8 GHz (D 820) to 3.2 GHz (D 840). Both cores in this CPU family come equipped with a 1 MB L2 cache, whereas the most current dual core processors in the 900 series make 2 MB available to each core. For the last year, Intel has brought no new models in the 800 series to market, because the company has switched its fabrication from a 90 nm process to a 65 nm one in the meantime, and has used this smaller building block size only for processors in the 900 series. But then out of nowhere, the old Smithfield core put in another appearance in the form of the Pentium D 805.

The Intel Pentium D 805 costs only $130 but incorporates a dual core - only a few users were in the know about this.

A rear view of the Pentium D 805, built for the LGA 775 socket.
Processor Number Clock Speed L2 Cache Multiplier FSB clock
Pentium EE 965 Dual 3724 MHz 2 MB 14x 266 MHz QDR
Pentium EE 955 Dual 3466 MHz 2 MB 13x 266 MHz QDR
Pentium D 950 Dual 3400 MHz 2 MB 17x 200 MHz QDR
Pentium D 940 Dual 3200 MHz 2 MB 16x 200 MHz QDR
Pentium D 930 Dual 3000 MHz 2 MB 15x 200 MHz QDR
Pentium D 920 Dual 2800 MHz 2 MB 14x 200 MHz QDR
Pentium 4 "E" 661 Single 3600 MHz 2 MB 18x 200 MHz QDR
Pentium 4 "E" 651 Single 3400 MHz 2 MB 17x 200 MHz QDR
Pentium 4 "E" 641 Single 3200 MHz 2 MB 16x 200 MHz QDR
Pentium 4 "E" 631 Single 3000 MHz 2 MB 15x 200 MHz QDR
Pentium EE 840 Dual 3200 MHz 1 MB 16x 200 MHz QDR
Pentium D 840 Dual 3200 MHz 1 MB 16x 200 MHz QDR
Pentium D 830 Dual 3000 MHz 1 MB 15x 200 MHz QDR
Pentium D 820 Dual 2800 MHz 1 MB 14x 200 MHz QDR
Pentium D 805 Dual 2666 MHz 1 MB 20x 133 MHz QDR

By comparison with all the other processors in this series, the D 805's relatively low clock speed of 2.66 GHz doesn't make much of an impression on store shelves. At 133 MHz (533 QDR), its front side bus clock rate is laughable when compared to state-of-the-art CPUs with 200 and 266 MHz speeds.

FSB clock Bandwidth
266 MHz (1066 QDR) 8.53 GB/sec
200 MHz (800 QDR) 6.40 GB/sec
133 MHz (533 QDR) 4.20 GB/sec

Out of the box and with no additional modifications, the Pentium D 805 is not even half as fast at exchanging data with the Northbridge chipset, when compared to leading-edge CPUs with 266 MHz FSB clocks.

Summary
  1. A Budget CPU At Top Speeds
  2. A Budget CPU At Top Speeds, Continued
  3. Inside the Pentium D 805
  4. The Secret Of The Multiplier
  5. 133 MHz FSB: Perfect For Overclocking
  6. How Is Breaking The 4 GHz Barrier Possible?
  7. How Is Breaking The 4 GHz Barrier Possible? Continued
  8. How Is Breaking The 4 GHz Barrier Possible? Continued
  9. Three Theories Where The Customer Comes Out Ahead
  10. Which Memory Clock Speed Is Most Suitable?
  11. The Right Chipset
  12. Keeping Cool When Power Consumed Tops 150 Watts at 4.1 GHz
  13. Keeping Cool When Power Consumed Tops 150 Watts at 4.1 GHz, Continued
  14. Power Consumption Levels Top 200 W
  15. Power Consumption Levels Top 200 W, Continued
  16. Energy Saving Functions Lack C1E
  17. Risk-free Overclocking, Including Heat Protection
  18. Ready For The 64 Bit Future
  19. Tom's Hardware Guides Overclocking Diary
  20. 3.33 GHz Remains Stable At Standard Voltage Levels
  21. 3.33 GHz Remains Stable At Standard Voltage Levels, Continued
  22. Trouble Free Operation At 3.60 GHz
  23. At 3.8 GHz Some Minor Voltage Increases Become Necessary
  24. Water Cooling Is Recommended For 4.0 GHz
  25. Water Cooling Is Recommended For 4.0 GHz, Continued
  26. Overclocking To 4.10 GHz Boosts Basic Clock Speed By 54 Percent
  27. Overclocking To 4.10 GHz Boosts Basic Clock Speed By 54 Percent, Continued
  28. Will The System Boot At 4.3 GHz?
  29. Benchmark Results Show Performance Increases Of Up To 54 Percent
  30. 3D, Continued
  31. 3D, Continued
  32. Video Editing / Video Encoding
  33. Video, Continued
  34. Video, Continued
  35. Audio Encoding
  36. Office Applications
  37. Office Applications, Continued
  38. Parallel Applications - Multitasking
  39. Synthetic Benchmarks
  40. Synthetic Benchmarks, Continued
  41. Synthetic Benchmarks, Continued
  42. Synthetic Benchmarks, Continued
  43. Summary Overview: Who's The Winner?
  44. Conclusion: The 4.1 GHz Dual Core Delivers Peak Performance For Pocket Change
  45. Conclusion, Continued
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