March 29, 2004 11:57 AM PST
Intel to reunite notebook, desktop chip architectures
Intel will adopt a common processor core for its notebook and desktop chips by 2007.
In the past, notebook chips derived from desktops. But with power consumption a growing problem, the desktop family will now come out of notebook designs.
Merom will derive from the Pentium M line of notebook chips, which run at slower speeds than the Pentium 4 line of desktop chips but consume far less power. The Pentium M and Pentium 4 are built around similar--but distinctly different--cores, and each has features the other doesn't.
The convergence of the two chip families through Merom means that desktop performance won't likely slow down, but the acceleration of megahertz will. Some notebook chips may creep into the desktop line with Jonah, a predecessor of Merom, due in 2006. A new chip-numbering plan that de-emphasizes megahertz will help Intel get around any thorny marketing issues.
"The Pentium M in most regards is very competitive with the Pentium 4 while running at dramatically lower clock speeds," said Nathan Brookwood, an analyst at Insight 64. "Power consumption and heat dissipation is almost as large an issue on desktops as it used to be in mobile."
Merom also appears to be a victory for the company's design center in Israel. The Pentium M line came out of that group and was co-managed by Mooly Eden, an Intel exec who now works out of Santa Clara. Other than this one, Intel's main microprocessor designs have come out of Oregon or Santa Clara.
The chips from Israel are easy to recognize because they all have code names that derive from there. Banias, the code name of the first Pentium M, was taken from an archeological dig. A new version of the Pentium M, code-named Dothan--another archeological site--is due in the second quarter.
The Israel design group was also behind the MMX multimedia technology. The group, however, also came up with the ill-fated integrated chip called Timna. Still, Intel president Paul Otellini signaled late last year that the company will likely once again try an integrated budget processor for developing nations.
Notebooks on top
Historically, Intel notebook and desktop chips shared the same basic core. Typically, Intel took its desktop chip and added some features, such as SpeedStep, to reduce power consumption and ran the chips at lower clock speeds. Because notebooks run on batteries, power consumption has been a more important consideration than with desktops.
That approach changed in 2000 with the release of the Pentium 4. The chip was designed to run at high speeds and perform different tasks simultaneously. Current Pentium 4s, for instance, run at 3.4GHz, while AMD's fastest chip runs at 2.4GHz.
Critics, however, have said that the fast speeds don't necessarily translate to greater performance. Despite the speed gap, Intel's and AMD's chips are extremely close in performance, with AMD's chips winning a number of benchmarks. More importantly, fast chips generate more heat and consume more power than their slower counterparts.
Intel executives have said that the company will move away from boosting performance through increasing megahertz, but the company's actions have often been inconsistent with that goal. This year, Intel launched a retooled version of the Pentium 4 code-named Prescott. Among other changes, Prescott came with a 31-stage pipeline, which functions like an internal assembly line. Older Pentium 4s had a 20-stage pipeline, the subject of criticism by some. The Pentium III had a ten-stage pipeline. Typically, a pipeline is lengthened only to boost speed.
"It's got a pipeline that lets them scale to insane frequencies," said Dean McCarron, principal analyst at Mercury Research.
Similarly, Intel president Paul Otellini announced late last year that the company plans to hit the 4GHz mark this year.
While working on the Pentium 4, Intel also began to develop the Pentium M (formerly code-named Banias), an energy-efficient chip for notebooks. While analysts have noted that the Pentium M shares characteristics of both the Pentium III and Pentium 4, it also contains features found in neither of its desktop relatives.
Among the novel architectural features is Micro Ops Fusion, which lets the chip combine routine instructions and tasks, thereby saving time and energy. Company executives have likened the process to a bunch of people at the airport sharing a cab, rather than taking separate taxis. Another feature, Advanced Branch Prediction, lets the processor better schedule tasks. Different parts of the chip, too, such as the system bus and even the Wi-Fi chips, shut down when not in use to conserve power. But the Pentium M doesn't currently sport features like Hyperthreading, which lets the Pentium 4 tackle simultaneous tasks.
Intel declined to comment on Merom, which first became known publicly by way of an Intel road map posted by PC Watch in Japan.
Although an excess supply of notebook chips this quarter is expected to slightly dent Intel's sales, Pentium M chips have sold fairly well. The chip line was credited with contributing to the strong growth in profits in 2003.
The Pentium M has also helped Intel enter the market for Wi-Fi chips. More than half of Pentium M notebooks come with Wi-Fi chips that were either made or resold by Intel, Anand Chandrasekher, vice president of the Intel Mobile Group, said in an interview last month.
Although the desktop and notebook versions of Merom will be based on the same core, Intel will likely build substantial differences into them, said McCarron. A desktop version, hypothetically, could come with a larger cache and only about 80 percent of the energy efficiency technology.
The company's new model number plan for selling its chips will also help it smooth this transition, McCarron added.
Intel now grades its chips by megahertz, but starting in May, the company's chips will come with model numbers: 700 class chips, like the 755, will be for notebooks; 500 class chips will fit into desktops, while 300 class chips will go into budget PCs. (A small class of 900 chips for supercharged desktops will also exist.)
Hence, Intel can flatten out megahertz but, by boosting performance in other ways, maintain a high model number.
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