Intel's Tukwila processor will be a significant departure from earlier Itanium models, but bigger changes will come with its sequel, Poulson.
When the Tukwila chip arrives in 2008, the biggest difference will be system-level changes such as how the chip plugs in, said Pat Gelsinger, general manager of Intel's Digital Enterprise Group. Poulson will bring changes to the chip itself.
"Tukwila is a fairly big system-architecture departure. Poulson will be a much bigger microarchitecture step in the Itanium line," Gelsinger said Tuesday in an interview at the Intel Developer Forum. "Poulson is a bolder step."
Breaking up major changes into smaller steps is a reasonable way to avoid pitfalls of wholesale changes, said Insight 64 analyst Nathan Brookwood. "Every time you throw everything up in the air at once, you increase the odds that when something lands, it's going to be broken, and it's going to be hard to figure out which."
Intel made a similar move with its Bensley platform, a package that combines the company's next-generation Xeon — first Dempsey and Woodcrest shortly thereafter — with a supporting chipset and network controller. "They are very different microarchitectures, but they use the same system interface," Brookwood said.
The major system-level change expected with Tukwila is a new method to connect the processor to the rest of the system. Intel doesn't comment on its particulars, but server makers have called the technology the Common System Interconnect. Those computer makers also say one major part of the interconnect is moving the memory subsystem controller onto the chip, a step that Intel's major competitors — IBM, AMD and Sun — have already made.
However, Intel declines to comment on interconnect details, and at least one key element has changed significantly: that Xeon and Itanium chips would share it, hence the "common" label. The first Xeon to use the interconnect, Whitefield, was cancelled in 2005 and replaced by Tigerton, which uses a variation of the current front-side bus interconnect.
Kirk Skaugen, general manager of Intel's Server Platforms Group, said the common platform still will arrive, though "in a later time" after Tukwila's debut.
Intel and HP, the initiator of the Itanium project and its biggest advocate, have begun trying to take the offensive with the chip family. The new assertiveness — including $10bn in Itanium technology and market development spending through 2010 from the two companies and other Itanium allies — comes after several years of troubles with weak customer acceptance and marketing challenges.
The most recent Itanium problem was the delay of the next-generation model, Montecito, from late 2005 to the second quarter of 2006. HP systems with the chip are expected this summer, HP has said.
At the same time, Intel pushed back Montvale, an update to Montecito, from 2006 to 2007, and pushed Tukwila from 2008 to 2009. On Tuesday, Skaugen said Poulson will arrive "out toward the end of the decade."
The delay stemmed from issues with timing circuitry within the chip, Gelsinger said. "We use some very sophisticated design techniques and clock technologies that were not as robust as we expected. It took some time to work through circuit electrical marginalities to get the part to be robust enough," he said.
To deal with the issue, Intel lowered the top clock speed 200MHz and stripped out one Montecito feature called Foxton that would have provided a 200MHz clock-speed boost when such a move wouldn't cause heating problems. Foxton isn't dead, though, Gelsinger said.
"The concept is a powerful one, and you will see it in our product line," including both Xeon and Itanium models, Gelsinger said.
Later this month, HP is launching its third-generation high-end Itanium server, based on a chipset code-named Arches. Initially, it will ship with current Madison models of Itanium, but HP will offer promotions later this year to encourage customers to upgrade their Integrity Superdome servers to Montecito.
It's not the only promotion in place. Through the end of April, HP is offering to halve processor costs in its Integrity line of Itanium servers. "HP, in conjunction with our processor partner Intel, is offering an incentive program to qualified customers whereby you can purchase new HP Integrity servers and get half of the processors in the servers at no charge," the company said on its Web site.
