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In a surprise announcement, Intel told PC manufacturers Tuesday that it has switched gears and will support both PC-133 SDRAM and Rambus dynamic RAM with its next generation chip, the Pentium 4 (formerly code-named Willamette). Previously, Intel has said that it would only support Rambus (RDRAM) memory with the Pentium 4.

RDRAM is a type of computer memory that is supposed to dramatically improve a PC's performance by delivering data to a processor at much faster rates than SDRAM, a widely used and relatively inexpensive form of memory. RDRAM has long been controversial because it is much costlier than SDRAM and has so far shown little performance return for its price premium.

The announcement by Intel means that PC buyers can now look forward to the Pentium 4's anticipated high performance without being required to use high-cost RDRAM. (For more on RDRAM performance versus SDRAM, see "Money For Nothing? Rambus Performance Falls Short.") The Pentium 4 is due out late this fall.

Motherboards that work with PC-133 SDRAM and the P4 won't be available immediately, said George Alfs, an Intel spokesperson. Alfs said the initial motherboard chip set released with the Pentium 4 will still be the planned model (code-named Tehama and likely to get an 850 designation), which only supports dual-channel RDRAM. This model will continue to be the Pentium 4's primary chip set, according to Alfs.

Intel decided to bring the SDRAM chip set to the roadmap of the Pentium 4 because of discussion with customers, and the company is investigating support for another high-performance memory technology, Double Data Rate (DDR) SDRAM, as well, Alfs said. AMD, Intel's archrival in the processor arena, had been the most prominent supporter of DDR until now. DDR is currently found in high-end graphics cards and should soon appear in AMD Athlon systems.

There has been speculation that the chip set supporting Pentium 4 and PC-133 SDRAM will appear in the second half of next year, well after Pentium 4's release. Alfs, however, would only say that Intel plans to release the chip set in 2001.

Rambus Nonplussed

Avo Kanadjian, vice president of worldwide marketing for Rambus, said he was not surprised by Intel's announcement. In his view, the announcement is a contingency plan, in case memory shortages continue and there isn't enough RDRAM to meet demand.

"Intel has to have flexibility to make their processor transition successful without any obstacles," Kanadjian said. But as far as he is concerned, if Intel can secure the amount of RDRAM it requires, it "makes no sense to have inferior SDRAM-Pentium 4 systems enter the market." He referred to Intel's consistent remarks about RDRAM's performance benefits, especially when coupled with the Pentium 4. At the Intel Developer's Forum in February, he mentioned, Intel demonstrated a system with up to 30 percent improvement in performance with Pentium 4 and RDRAM over SDRAM Pentium III systems. He also cited projections made in May by Dataquest in which RDRAM is expected to make up nearly 30 percent of the market in 2001, growing to over 50 percent in 2002.

Kanadjian reiterated the company's position that RDRAM is the best memory architecture for processors over 1 GHz. He pointed out that there is about a year between now and when the Pentium 4-SDRAM chip set is due out, and in that time RDRAM's value should improve versus SDRAM, both in lower cost and greater supply, making the SDRAM chip set unnecessary.