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How Is Breaking The 4 GHz Barrier Possible?

A 4.1 GHz Dual Core at $130 - Can it be True?
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A closer look at the processing cores in the 805 CPU reveals that the device is fabricated with a B0 product code (stepping). The first core in the 800 series on which this CPU is based was fabricated using the older A0 version instead.

The first items Intel fabricated in the 800 series were delivered with A0 version cores


The successor series used the B0 version cores, and this is the series to which the Pentium D 805 cores belong.

There aren't any significant differences between the two versions when it comes to energy saving functions or instruction sets, but it's easy to recognize from the B0 version that the Pentium D 805 really belongs to the second production series for this CPU. The motivation for a version update usually comes from further optimizations to the circuit layout or fabrication process, as well as corrections for design or behaviour errors. On all counts, the B0 version is an improvement over the older A0 version. Since this version could handle CPU clock rates of 3.2 GHz at the beginning of the series without any problems, a consequence of these improvements is that all B0 version CPUs should be able to handle CPU clock rates of at least 3.2 GHz. This was the theory we formulated before we started testing the Pentium D 805.

Processor Clock Rate Version sSpec Number
Pentium D 840 3.20 GHz A0 SL88R
Pentium D 830 3.00 GHz A0 SL88S
Pentium D 820 2.80 GHz A0 SL88T
Pentium D 840 3.20 GHz B0 SL8CM
Pentium D 830 3.00 GHz B0 SL8CN
Pentium D 820 2.80 GHz B0 SL8CP
Pentium D 805 2.66 GHz B0 SL8ZH
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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