SANTA CLARA, Calif. -- Intel Corp.'s support of Direct Rambus DRAM in next-generation PCs has taken a surprising twist, as the company will now base its entire 2000 mobile computing platform upon synchronous DRAM, industry sources said.

Earlier this week, sources said Intel has pulled the plug on Greendale, which was to be the company's first mobile chip set with support for Direct Rambus memory, and will instead look to devices that interface with PC100 and PC133 SDRAM (see Dec. 14 story).

The cancellation notice was included in a late November road map distributed to OEMs, but gave no reason for the decision. In a section of the presentation that details Intel's perspective on the mobile market, the company indicated that its notebook-PC efforts will include a "product mix optimized for SDRAM."

Asked about the Greendale's cancellation, an Intel spokesman reiterated the company's policy of not commenting on programs in development. He said Intel still expects to bring a mobile Direct Rambus chip to market in 2000 or 2001, and added that the company will support all customer needs for mobile Direct RDRAM.

Specifically, the Intel road map notes that the mobile version of the Solano-2, an integrated graphics chip set, will be introduced late in the third quarter of 2000 and will enter mainstream volume production in the fourth quarter. That chip set, which will include 100- and 133-MHz front-side bus options, will also — for now — exclusively feature PC100 and PC133 SDRAM memory interfaces.

Industry sources could not say which graphics core will be built into the Solano-2, but the chip set is believed to feature an option to an external AGP2X or AGP4X graphics connection.

Intel's commitment to Rambus Inc.'s Direct RDRAM also seems dubious in the desktop-PC segment. In a series of suggested PC configurations designed to ship during the first half of 2000, the road map slates only the highest-end skew to contain Direct RDRAM -- and the highest-speed PC800 version at that.

Sources believed the road map's SDRAM focus was rooted in cost concerns, given that Direct RDRAM still carries a premium several times that of conventional PC100 and PC133 SDRAM. Intel's road map predicts that overall DRAM prices and demand will likely decline in the first half of next year, but increase over the latter half.

Mountain View, Calif.-based Rambus--the designer of the Rambus interface--said Direct RDRAM is uniquely suited for mobile applications because of its several power-saving modes, including standby and nap. However, critics have charged that these modes, while saving power, come at the expense of system performance because of the latency issues associated with powering the Rambus chips.

Additionally, persistent pricing concerns have apparently made Rambus' technical advantages less compelling. Rambus executives also recently announced a strategy shift towards communications-centric devices, although the company said it will continue to fully support PC products.

Other Intel road map revisions focused more on desktop PCs. Sources confirmed an earlier report that a 750-MHz Coppermine processor with a 100-MHz front-side bus will join two 800-MHz Coppermine chips, with 100-MHz and 133-MHz bus options, on Dec. 20.

However, the products are expected to be in limited supply. At the end of the second quarter 2000, Intel will introduce an 866-MHz chip with a 133-MHz bus that will ship in volume during the third quarter, at which time a 933-MHz chip will be announced. Willamette, which online reports have pegged as the Pentium IV, will debut in the early fourth quarter at only 800 MHz, sources said.

In the desktop value segment, the launch of the 566-MHz version of the Celeron has been accelerated to the first quarter 2000. Timna, a processor integrating a memory controller and graphics core, is still scheduled to be introduced late in the third quarter, sources said.