Intel's Yonah first step toward new chips

Yonah, Intel's dual-core mobile processor for the first quarter of 2006, is every bit as revolutionary as the single-core Pentium M processor that changed the way Intel designed its chips, company executives said Tuesday at the Intel Developer Forum (IDF).

Tuesday's big news at IDF was confirmation of the company's plans to base forthcoming dual-core processors for desktops, notebooks, and servers on a common architecture inspired by the Pentium M. While much has already been revealed about Yonah, it is basically the rough draft for those chips and a more elegant design than the company's first attempts at dual-core PC processors.

Yonah is not just two Pentium M cores slapped together on the same silicon die, said Ronny Korner, head of presilicon validation for mobile platforms at Intel. The separate cores are based on the Pentium M, but they work very closely together to save power and improve performance by sharing data and monitoring the workload on each core, Korner said.

The Pentium D, Intel's dual-core chip for desktop PCs, was simply two Pentium 4 processors crammed onto a single chip with little time to overcome problems such as package design and signaling interference, an Intel engineer told attendees at the Hot Chips conference last week. Yonah, on the other hand, was designed from the beginning to overcome some of the challenges of producing chips with two processing cores, Korner said.

Yonah's two processor cores each have their own bank of cache memory, which stores frequently used data close to the main CPU (central processing unit) where they can be accessed more quickly than data stored in main memory. Those cores share information about the contents of that cache directly with each other, unlike the Pentium D's caches, which exchange information by sending a signal out of one core, off the chip, and back onto the chip to the other core.

Intel also designed a deeper sleep state for Yonah that clears the cache memory of data in order to save power, said Mooly Eden, vice president of the Intel Mobile Platforms Group and the leader of the design team that produced the original Pentium M. During extended periods of inactivity, Yonah saves the contents of the cache memory to the main memory and then shuts off those transistors. Memory requires an electrical charge to store data, so Intel can reach even lower levels of power consumption by turning off these transistors, Eden said.

Yonah will consume as much power as its single-core predecessor as a result of this and other power-saving features built into the chip, Eden said. This is despite the fact that Yonah contains two processor cores and millions of additional transistors, he said.

Intel also disclosed a number of power-saving technologies built into the 945 Express chipset and Pro/Wireless 3945ABG chips that will accompany Yonah in Napa, a forthcoming platform that combines the three. Notebooks based on Napa will offer longer battery life with a significant increase in performance over older Pentium M notebooks, Eden said.

For example, the 945 chipset will be able to automatically dim a notebook's display based on the amount of power left in the battery in order to extend the lifetime of that charge, Eden said. On the graphics side, the chipset can avoid processing graphical data that does not affect the quality of the final image, he said.

Yonah and the entire Napa platform will launch by March of next year. Merom, the notebook chip based on Intel's new processor architecture detailed earlier on Tuesday, will add virtualization, security and 64-bit technologies to Intel's notebook lineup when in arrives in the second half of the year, Eden said.