Rambus revs up chip speed

The memory chip maker says it will increase the clock speed of its RDRAM chips from 800MHz to 1.2GHz by 2005. It hopes to crack the mainstream PC market.

Rambus is releasing new memory designs that the company hopes will help win its technology a place in mainstream computers, a market that has so far eluded the company.

The company, which designs and licenses Rambus Direct RAM (RDRAM), plans to increase performance of its memory by a factor of six over the next four years.

The Los Altos, Calif.-based chip designer has unveiled plans to increase the clock speed of its RDRAM technology from 800MHz to 1.2GHz by 2005. The company also plans to add more circuitry so 64 bits of data can be sent with each tick of the clock, instead of the current 16 bits. The result: RDRAM will be able to transfer information from 1.6GB per second to as high as 9.6GB per second.

Rambus hopes that the extra performance will allow RDRAM keep pace with PC processors' increasing clock speeds and help boost overall performance for high-end PCs such as those with Intel's Pentium 4 chip.

At the same time, Rambus hopes to expand its slower RDRAM into less-expensive PCs or into servers--markets the company hasn't cracked despite firm support from Intel.

The new chips with increased bandwidth will come in three speeds: 800MHz, 1066MHz and 1.2GHz. The introduction of the faster memory modules, the company asserts, should help drive down prices on current 800MHz RDRAM, which still costs much more than its ubiquitous competitor, synchronous dynamic RAM (SDRAM). If RDRAM prices drop, the slower versions of RDRAM could end up in low-cost desktop PCs and in servers. The faster RDRAM could be used in workstations, Rambus said.

"The DRAM manufacturers and Rambus have been working aggressively to lower the cost. Price is a function of supply and demand, but costs (of manufacturing) are now coming down to the range of SDRAM," a Rambus representative said Friday.

Meanwhile, SDRAM is overcoming cost obstacles of its own. The availability of next-generation SDRAM, known as double-data rate (DDR) SDRAM, is increasing. The price difference, on the other hand, compared with the previously fastest 133MHz SDRAM is diminishing.

DDR SDRAM, which comes in speeds of 200MHz and 266MHz with data transfer rates of 1.6GB per second and 2.1GB per second, is found in desktop PCs that use Advanced Micro Devices' Athlon processor.

On Friday, 128MB modules of 800MHz RDRAM were selling for as low as US$59, while 266MHz DDR SDRAM modules were selling for as low as US$26, and 133MHz SDRAM for as low as US$13, according to PriceWatch.com.

Up to now, Rambus' biggest supporter has been Intel, which uses Rambus memory in its high-end PCs. Despite criticisms of RDRAM's high price, Pentium 4 computers currently can use only Rambus memory. But later this year, Intel's new 845 chipset will permit use of SDRAM with Pentium 4 computers.

An Intel spokeswoman said the chipmaker will evaluate the upcoming RDRAM designs but gives no assurance of support yet.

"We are evaluating what they have on the desktop," the spokeswoman said.

However, she added, "a lot of things have to coalesce" for Intel to adopt it. Evaluating the new technology "doesn't necessarily mean things will line up. We will have to see".

Rambus will first step up from 800MHz to 1066MHz next year. Intel potentially could support the 1066MHz RDRAM: Intel's Pete MacWilliams said recently that Intel could match the faster memory by increasing the bus speed of its Pentium 4 chip from 400MHz to 533MHz.

It's still unclear if anyone aside from Intel might use the faster memory. AMD, for example, holds an RDRAM license but has yet to use it. AMD has said it prefers DDR SDRAM for Athlon desktops.

Rambus will try to sway tough customers like AMD by augmenting its RDRAM frequency increases with the higher bandwidths. The company will tweak its Rambus Inline Memory Module (RIMM) design by adding a second 16-bit channel to the memory controller. The resulting 32-bit connection will help increase peak bandwidth to between 3.2GB per second and 4.8GB per second, depending on the speed of the chip.

The addition of two more channels at a later date, for a total of four 16-bit connections, will allow for a 64-bit interface. The result will increase bandwidth to between 6.4GB per second and 9.6GB per second. The highest bandwidth RDRAM module will contain 1.2GHz RDRAM technology and offer a 64-bit interface. This chip, pumping out 9.6GB per second of peak bandwidth, is expected in 2005.

Rambus has its work cut out for it as it tries to convince memory chip manufacturers and computer makers to embrace its memory, and SDRAM has a few more tricks up its sleeve. A technology known as DDR-2 is in development. Early indications are that DDR-2, based on DDR SDRAM, will increase bandwidth to 4.8GB per second and lower costs at the same time.