Obscure CPUs: Pentium D 900 series with 533 MHz FSB
There are different ways of identifying new and/or obscure processors, and one of the methods involves searching for part numbers, leaked in various Product Change Notifications, or via Intel MDDS database. These days, most of this information is useless because part numbers of Nehalem-based and newer processors cannot be deciphered. It was much simpler with Core, Netburst and older processors, though. Translating part numbers into more meaningful information, such as a package type, core name, family brand, frequency, and the size of the last level cache, was easy using tables like this Intel identification table. Using this identification table to decode unknown part numbers from published PCNs, we can find out that, for example, Intel worked on or planned Northwood processors in socket 775 package, or that there were Pentium D 9xx series CPUs with 533 MHz FSB. While these facts are entertaining, they are useless to us as we don't know for sure if the parts went into production or not... unless we receive a confirmation from Intel that they did, or see the parts in the wild.
Existence of Pentium D microprocessors with 533 MHz Front Side Bus frequency was recently confirmed when Intel added specifications of these chips to Pentium D pages in Intel's ARK database. Apparently, Intel produced 4 different Pentium D 533FSB CPUs with processor numbers 903, 913, 923 and 933, clocked at 2.8 GHz, 2.93 GHz, 3.06 GHz and 3.2 GHz respectively. Remaining features of these processors seem to be in line with known production Pentium D parts with 800FSB: Presler core, 4 MB L2 cache, and no HyperThreading. The ARK database also shows Pentium D 970 model with 3.8 GHz clock frequency - yet another microprocessor, that was never released.
At this time, we can only speculate that these processors were produced and shipped, perhaps in very small quantities, otherwise it wouldn't make any sense to add them to the ARK database. Intel website doesn't show part numbers and S-Spec codes for Pentium D 9x3 series and Pentium D 970, however we can guess this information from processors' specifications:
Update (Jan 25): Intel removed specifications of the Pentium D 9x3 and 970 microprocessors from the ARK database. They are still available in Google cache, though. See, for example, Google cache for Pentium D 903. Also, we corrected processor frequencies in the table at the end of this article.
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