Twenty years ago today, Intel launched the Pentium 60 CPU and changed the computing world for ever. Believe it or not, a revision of the original Pentium core still lives on today, in Intel's bleeding-edge, 50-core Xeon Phi -- a plug-in coprocessor that ushers us towards exascale supercomputing.
The Pentium 60 (pictured above), based on the P5 microarchitecture (the name Pentium is derived from the Greek word for five, pente), had 3.1 million transistors and was built on an 800 nanometer process (the same as Intel's 486 processors, if you had one of those). The Pentium 60 used the 5-volt Socket 4, but Intel quickly switched to the 3.3-volt Socket 5 with the 600nm Pentium 75 (which uses the same P54C architecture as the Xeon Phi).
For a while, Pentiums were slot-loaded, rather than pinned. While the early Pentiums were nothing to write home about (they were barely faster than the 486DXs that they replaced), the P6 architecture -- which debuted in the Pentium Pro, but wouldn't truly find its feet until the Pentium 3 -- was a complete and utter beast. In terms of comparative performance, Intel certainly had the lead over x86 clones (AMD, Cyrix) throughout the Pentium 1 and 2 eras, but it wasn't until the P3 Coppermine/Tualatin cores, released in 1999, that Intel performance edge really began to show. And then it all went wrong.
After the P6 architecture came Netburst, a very different architecture that was designed to reach huge clock speeds (Tualatin maxed out at 1.4GHz, while Prescott could hit 3.8GHz) -- but at the expense of actual performance. Pentium 4s ran very hot and very noisy, and later revisions ultimately performed quite well, but ultimately the architecture was a misstep that allowed AMD to swoop in and capture the performance crown with the Athlon and Athlon 64.
Around the same time as the Pentium 4/Athlon fracas, the Pentium 3 (P6) core lived on in Intel's new Centrino Pentium M mobile chips (Banias/Dothan), which were truly sensational chips. Intel, reeling from the biggest loss it's ever had in the x86 space, eventually produced Yonah in 2007, the dual-core version of Banias/Dothan. Yonah was quickly followed by Intel's Core architecture at the end of 2007, which was again based on the same P6 architecture that first appeared in the Pentium Pro, all the way back in 1995.
This brings us up to the Core Duo era, and the rest -- Nehalem, Sandy Bridge, Ivy Bridge, and soon Haswell -- is history. Intel still uses the Pentium brand, but today it refers to entry-level versions of Core processors that have fewer cores and many features (such as Hyper-Threading) disabled. As we mentioned at the beginning of the story, the Xeon Phi uses almost exactly the same core as the Pentium 75 (P54C) -- but really, these cores are just a sideshow for some new, massive vector units.
So there you have it: Happy birthday, Pentium!
Now read: 4004 to Sandy Bridge: A walk down CPU memory lane
