Intel Details Upcoming Itanium 2 Chips

Intel plans to introduce multithreading and 24MB on-chip caches to its Itanium 2 processor family, a company executive has acknowledged.

Itanium's first multicore processor, code-named Montecito, will have multithreading when it is released in 2005, said Ajay Malhotra, the director of enterprise marketing and planning for Intel's Enterprise Systems group. The chip will also have 24MB of on-chip cache, much more than the 9MB available in Intel's current Madison processors.

"Not only is Montecito dual-core, it has massive amounts of cache and, quite significantly, multithreading," he said.

Multithreading allows a single processor to operate like multiple processors, so with multithreading, a dual-core Montecito would appear to the operating system to have at least four processors.

Another Approach

Intel's follow-up to Montecito, the 8-core Tanglewood processor being developed by a team of former Alpha processor developers, will also be multithreaded, but it may take a different approach to the problem, Malhotra said. It will have seven times the performance of current Madison Itanium 2 processors, an improvement that will primarily be driven by how Intel implements multithreading and how the company manages to link Tanglewood's cores together, he said.

"[Chip] frequency will play a role, but it will be eclipsed by improvements in multicore and multithreading," he said.

Multithreading is particularly difficult to bring to the Itanium "in order" processor architecture, said Nathan Brookwood, an analyst with industry research firm Insight 64 in Saratoga, California.

"I'm amazed that they can do it because the secret for Itanium performance is very sophisticated compilers and multithreading is not the sort of stuff that compilers can accommodate," he said.

Intel's move to 24MB of on-chip cache is less remarkable, he said. "They're taking two Madison 9MB and smashing them together on a chip, so you knew it was going to be at least 18MB."