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Intel's Pentium III 1.2GHz processor

Octagenarium III

After some investigation, Intel pulled the 1.13GHz Pentium III back from the market, and a long hiatus ensued. The Pentium III languished at gigahertz and lower clock speeds while the company concentrated on its new, high-clock-speed burner, the Pentium 4. Equipped with a brand-new NetBurst microarchitecture, oodles of platform bandwidth, and the power of a whole new digit after its name, the P4 was Intel's best tool to combat AMD's advancing Athlon.

The P4 was designed to run at extremely high clock speeds, and it's already reached 1.8GHz when built on the same fabrication process as the original, stillborn 1.13GHz Pentium III. Meanwhile, AMD's assault has continued. The Athlon has added faster DDR memory and a 266MHz bus, and AMD has pushed it to 1.4GHz. At that speed, it was the highest performance desktop PC processor available last we checked. Even the mighty Pentium 4, with all those megahertz available to it, couldn't best the Athlon.

All of that may turn around soon, however. The Athlon is a great design, but one could argue the processor industry is primarily about manufacturing. On the manufacturing front, Intel has just taken a decisive lead, and the processor we're reviewing here today is the first evidence of that fact.

Things really do shrink with age
Intel has managed to push the Pentium III design past the 1.13GHz barrier by manufacturing the chip on its brand-new fabrication process. Previous "Coppermine" PIIIs were built on Intel's 0.18-micron fab process. (The "micron" designation refers to the width of features on the chip. If 0.18 microns sounds extremely small, you're getting the idea. This is how they pack millions of transistors into a thumbnail-sized area.) This new Pentium III, code-named Tualatin during its development, is built on a brand-new, 0.13-micron fab process. This new process is smaller, but that's not all. Intel is now using copper interconnects instead of aluminum, and they're using low-capacitance dielectrics, as well. (Despite the name, Coppermine chips used aluminum interconnects.)

All of these things will allow chips to run more efficiently, cooler, with less power, and at higher clock rates. The Pentium III 1.2GHz requires only 1.475V core voltage, and it's a model of stability. We didn't experience a single crash during our testing.

Beyond the die shrink, the new Pentium III isn't radically changed from its previous renditions. The desktop version has the same L2 cache configuration as the Coppermine, but the mobile and server versions have twice the cache—512K—onboard. Beyond that, the only big change that might affect performance is a new data prefetch logic. Like the P4 and AMD's new "Palomino" Athlons, the new PIII will try to anticipate what data a program will need next and pre-load it into the chip's L2 cache. In certain situations—especially on the chips with 512K L2 caches—data prefetch could improve performance. Unfortunately, the PIII is still saddled with a 133MHz front-side bus and PC133 memory, so don't expect huge gains.