Intel Corp.'s Pentium 4 Marches On

Electronic News, Sept 17, 2001 by Alex Romanelli

845 chipset now supports PC-133

Intel Corp. last week began shipping its Pentium 4 845 chipset, designed to use the Santa Clara, Calif.-based company's flagship processor in high-volume, mainstream consumer and corporate desktop PC markets.

The 845 chipset's most significant difference from its predecessor, the current 850 chipset, is its support for PC-133 SDRAM memory technology. This establishes it is as an alternative to the 850, which exclusively supports Rambus Inc.'s costlier Rambus DRAM (RDRAM) memory.

Intel (nasdaq: INTC) INTC) plans for the 845 chipset to support double data rate (DDR) SDRAM in the first quarter of 2002 when Intel said it would be able to manufacture the DDR chipset in high volumes. DDR is considered to offer similar performance to RDRAM but at a lower cost.

The 845 chipset provides a significant performance improvement over Intel's 815 chipset, which uses a Pentium III chip, Intel said. In comparative tests on mainstream applications, a 1.8GHz P4 using the 845 chipset ran between three to four times faster than a 1GHz PIII chipset using the 815 chipset, said Jeff Austin, marketing manager for Intel's desktop platform group.

In addition, the 845's memory controller hub supports a 400MHz system bus and has a 1.5V AGP4x interface allowing 1Gbyte/sec. of graphics bandwidth.

Supporting the more mainstream PC-133 SDRAM will allow wider adoption of the chipset, Austin said. Intel wants this chipset to be used by IT departments worldwide, he said. To achieve this, the chipset has been competitively priced at $42 each in quantities of 1,000.

According to Intel's calculations, this puts a 1.8GHz P4 processor with an 845 chipset in the sweet spot--the optimal point in the marketplace for a satisfactory compromise between price and performance.

"You can never have enough performance," Austin said. "The more performance you have, the better your experience will be."

Intel said it designed the chipset to have enough headroom to make it viable for the next generation of software applications and technology.

Improvements to the internal architecture of the chipset include 256bit internal data paths, giving it four times the internal data transfer capability over previous generations. The 845 has an in-order queue (100) depth of 12, compared to the 850's depth of 8.

The chipset does not need a higher IOQ because of its superior memory performance, Austin said. The MCH has also been designed with a flexible memory refresh so it completes memory refreshes during low priority activity, freeing up the available memory bandwidth. The chipset adds the write cache to the memory, rather than the buffer, providing faster access and more bandwidth across the platform, Austin said.

Board-level enhancements include dynamic bus inversion, allowing the chipset to invert the data to minimize I/O switching. Nine months ago it would have been impossible to manufacture the chipset's staggered BGA in high volumes, Austin said. The chipset also has source-synchronous memory clocks.

The 845 is manufactured on a 0.18-micron process and the 850 chipset on a 0.25-micron process.