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Intel looks to move past false starts with Rambus
By David Lammers
EE Times
(03/01/01, 6:28 p.m. EST)
SAN JOSE, Calif. — Intel Corp. and the three major vendors of Rambus DRAMs say they are ready to deliver on the long-promised RDRAM technology, following what Intel Fellow Peter MacWilliams this week called "many false starts" in the effort to bring the embattled architecture to the mainstream desktop market.
The stakes could hardly be higher.
Intel's corporate health depends on quickly ramping the Pentium 4 processor and on seeing the memory vendors sharply increase RDRAM shipments. For now, Intel's 850 is the only chip set to support the Pentium 4, and the 850 only supports RDRAMs.
The company is readying a double-data-rate SDRAM chip set for first quarter 2002 shipment. But at least one chip-set vendor, ServerWorks Inc., intends to beat Intel to the punch by rolling a Pentium 4-based chip set later this year that will rely on DDR memories to feed the wide Pentium 4 front-side bus.
At the memory track of the Spring 2001 Intel Developer Forum here, Intel's MacWilliams said the "hiccups" and "worst-case corners" for Intel's Rambus program are in the past and affirmed that Intel wants to see "the vast majority of the Pentium 4 systems ship with RDRAMs."
Sensing opportunity, top executives from Samsung Electronics, Elpida Memory and Toshiba all went to the stage at IDF to promise sharply increased RDRAM production next quarter.
Samsung senior vice president Jon Kang said Samsung will increase RDRAM production to 12 million 128-Mbit equivalents per month in the next quarter, from 8 million now, and that it expects RDRAM yields to approach 100 percent by June. By year end, Samsung will ship 15 million or more 128-Mbit RDRAMs per month, depending on market demand.
To support Samsung's ramp, Intel announced this week that it is investing an undisclosed amount in Samsung so that the South Korean company can quickly install more RDRAM testers at its memory fabs in Kihung.
To reduce the price differential between Rambus-in-line memory modules (RIMMs) and synchronous-DRAM-stuffed dual-in-line memory modules (DIMMs), Intel is offering system vendors a rebate of about $65 for RIMM purchases. Two 64-Mbyte RIMMs are required to feed the two Rambus memory channels, costing about $110 or more. With today's depressed prices for SDRAMs, a 128-Mbyte DIMM is only about $40-45. Intel started the program about two months ago to increase adoption of the RIMMs at system OEMs.
Elpida — the company formed last year from the combined DRAM operations of NEC Corp. and Hitachi Ltd. — will ship 3 million to 4 million 128-Mbit and 144-Mbit Direct Rambus DRAMs this quarter. Shipments are slated to increase to 10 million for the April-June quarter, said Elpida president Kenji Tokuyama.
Starting in May Elpida will switch production to a 288-Mbit RDRAM and begin to terminate the 128-Mbit part over the summer. A 300-mm fab now being built in Hiroshima will begin wafer starts at the end of this year, further increasing Elpida's RDRAM production capacity.
Shozo Saito, general manager of the DRAM operation at Toshiba Corp., also promised a steep ramp of RDRAM production this year and a switch to a 288-Mbit part in the third quarter.
But other major DRAM vendors, including Micron, Infineon and Hyundai, are mired in legal battles with Rambus (Mountain View, Calif.) over synchronous-DRAM patents that apply to both SDRAMs and the rival double-data-rate (DDR) memories on which Advanced Micro Devices Inc. and Taiwanese chip-set companies are banking. If those companies stay on the sidelines, healthy price competition in the RDRAM market could be delayed.
Dieter Mackowiak, senior vice president at Samsung Semiconductor (San Jose, Calif.), said RDRAMs still have a 20 percent to 30 percent larger die size than SDRAMs and DDR memories. That contributes to a still-hefty price premium for the RDRAMs: A PC800 RDRAM costs about $18, compared with $10 for a PC266 DDR part and only $5 for an SDRAM with a 133-MHz speed and a latency of two clock cycles.
As the industry moves to 288-Mbit parts, that die size penalty will decline to 5 percent or so, Mackowiak added.
Insurance policy
As an insurance policy for companies that prefer to stick with SDRAMs, MacWilliams said that Intel is preparing the Brookdale S (for SDRAM) chip set, which will marry the Pentium 4 with the PC133 SDRAM. Many corporate customers may prefer the "stable" SDRAM technology, despite its much lower bandwidth, he said. In the first quarter of 2002, the DDR version of that chip set, Brookdale D, will begin shipping.
Intel plans to support a PC200 form of DDR, rather than the PC266 DDR memories that AMD and the Taiwanese chip-set vendors support.
"We are looking at 266, but we have our doubts," MacWilliams said. "We learned some significant lessons during the RDRAM program about high-speed memories. PC200 is our current target, and we believe there are a lot of platform issues" that go beyond the DDR memory itself, involving the modules and system design.
"With RDRAM, it seemed like every week we had to deal with another data-pattern-specific fault," MacWilliams said. "We would run a piece of software, find the root cause of fault, adjust our test patterns and make changes. The next week it would be a different pattern. We eventually got pretty good at solving these things.
"With PC266, we may get it to work, but for the personal computer it is not clear that it is worth all of the effort."
Intel and the DRAM vendors plan a shift to a simpler RDRAM bank structure, with four independent banks rather than the 16 dependent banks now commonly used. That will allow for a simpler redundancy scheme, a smaller die size and a lower cost premium over competing memories. The 4i parts will move into volume production next year as the DRAM vendors bring the 288-Mbit designs to market.
Intel wants to avoid any more stumbles with RDRAMs. Since the first Rambus-based platforms were introduced at Comdex/Fall 1998, Intel has struggled with its 820 chip set, the high prices of RDRAMs, and the stark reality that PC133 SDRAMs were a fine match for the Pentium III.
MacWilliams said that, in retrospect, the relatively narrow, 100-MHz front-side bus of the Pentium III had not been a good match with RDRAMs, and the Accelerated Graphics Port (AGP) and PCI had not exercised the overall memory bandwidth as much as Intel had expected.
Are the painful lessons of the past few years poised to pay off at last for Intel? Or will the company's dependence on the Rambus memories create another series of regrets and revised strategies?
Analyst Linley Gwennap said "it is going to be an interesting couple of quarters. I'm not sure that the high prices for RDRAMs are holding back P4 sales right now. But the DRAM industry has to pull off a steep ramp over the next few quarters to meet the goals that Intel has set with the P4. To move that processor into the $1,000 to $1,200 desktop market — I don't think you can do that with Rambus anytime this year.
"Intel will bring down the price of the P4, but without equivalent reductions in the price of the RDRAMs it will be hard to make that strategy work."
Intel is moving a shrink design of the P4 — the Northwood version — to its 0.13-micron process late this year. By then, other DRAM vendors may have settled their legal disputes with Rambus.
Business sense
Infineon, for example, is actively developing RDRAMs at the 256-Mbit density and is working to gain validation, said Dave Mooring, president and chief operating officer at Rambus. "For many of these companies, there is a separation between the legal situation and what they are doing on the technical and business side," Mooring said.
"The number of vendors supporting RDRAM is not as high as we had expected," Intel's MacWilliams acknowledged. "Ideally, Micron, Infineon and others will get beyond the legal situation with Rambus."
Richard Gordon, principal memory analyst at Dataquest Inc., said he believes RDRAMs will become the dominant memory architecture for desktops and that AMD will support an RDRAM architecture eventually.
"At this IDF, Intel was not wishy-washy about their support for Rambus. They came out and backed Rambus and said, 'We don't think DDR will fly in the mainstream desktop market,' " Gordon said. "Sure, they have a backup strategy with DDR; but for the first time in a while, they said, 'This [Rambus] is the deal.' "
At the IDF memory track, MacWilliams' remarks about DDR were "things that some people didn't want to hear," Gordon said. "But my reading of the situation is that the most important thing for Intel is the P4, and they are not going to let anything compromise that ramp. They will do anything they have to do to accomplish that, including rebates, investments in the DRAM vendors, whatever it takes." |
