Intel's Coppermine Recaptures Speed Crown

Intel leaps ahead of Advanced Micro Devices' Athlon processors with the release Monday of its "Coppermine" chips, a line of Pentium III CPUs that hit 733 MHz.

The megahertz jump tells only half the story. Intel's recent PIII speed increases looked good in the advertisements but didn't make productivity applications work much better. PC WorldBench 98 tests of the handful of new systems sporting Coppermine technology found some eye-popping performance gains.

The speed jump reverses the trend of earlier CPU releases this year, which saw faster chips without significant boosts to application speed. For example, PIII-550 systems ran PC WorldBench 98 apps just 5 percent faster than the average PIII-500 machine. The PIII-600 systems ran them just 4 percent faster than a typical PIII-550 PC. Neither gain was noticeable.

Thanks to a design improvement, however, the new PIII chips give everyday apps a potent shot of adrenaline.

The Coppermine line comes in a confusing variety of mix-and-match options, from 733 to 500 MHz, with 133- or 100-MHz system buses and several main memory options. PC World tested a Micron PIII-733 home machine with 133-MHz virtual channel SDRAM, and a Hewlett-Packard PIII-667 corporate desktop with PC-800 RDRAM. For a peek at AMD's best, we evaluated a Compaq home system carrying the 700-MHz Athlon and PC-100 SDRAM.

Besides the performance boosts, Micron's and HP's new power machines are surprisingly good values. The loaded Micron speed champ costs just $2377.

New Chips, New Game

What distinguishes the new Coppermine PIII chips from their Pentium III predecessors? With Coppermine PIIIs, Intel uses a .18-micron manufacturing process that squeezes more chips out of each silicon wafer. They do it by using smaller, closer circuit lines and transistors. The smaller chips run faster and throw off less heat. The process also lets Intel put a 256KB level-2 memory cache on the chip to pump up your most-used software.

L2 cache plays a key role: A processor uses it to avoid sending requests via the slower system bus to main memory. Level 2 cache guesses what data an application will need and keeps it on hand, near the CPU. A Coppermine PIII's on-chip L2 cache (or Advanced Transfer Cache, as Intel terms it) works at full speed--which today means as fast as 733 MHz. Older PIII chips rely on off-chip Level 2 caches that run at only half the processor's speed. The fast cache especially boosts Microsoft Office and similar apps that stash many pieces of information there.

Some new PIII machines also use a 133-MHz system bus, though our tests indicate it doesn't offer much benefit yet, compared to the standard 100-MHz bus. (Intel plans to push processor speeds past 800 MHz next year, at which point a 100-MHz bus won't be able to keep up.) Intel upped the Coppermine PIII's efficiency, too, with a technology called advanced system buffering. This lets the CPU send a few more requests through the system bus at a time.

The PIII-600EB, -667, and -733 desktops use a 133-MHz bus; PIII-600E, -650 and -700 machines use a standard 100-MHz bus. (An E suffix indicates on-chip L2 cache, while B indicates 133-MHz bus support. These names distinguish 600-MHz Coppermine chips from the original PIII-600.) AMD Athlon systems like our Compaq Presario boast a 200-MHz bus. But they won't fully capitalize on the bus speed until faster memory arrives.