Both processors, Sun's eight-core Niagara 2 and Fujitsu's dual-core Sparc64 VI, run Sun's Solaris operating system. However, they are aimed at different markets. Niagara 2 is for lower-end servers running Java or Web server software, while the Sparc64 VI works in higher-end servers with numerous processors that can handle tasks such as working with massive databases.

Company representatives speaking at the Fall Processor Forum here promised significant gains over the chips' predecessors--the first Niagara (now called UltraSparc T1) and the single-core Sparc64 V.

On integer processing--which represents the bulk of server tasks--the dual-core design of Sparc64 VI gives twice the performance per chip socket as Sparc64 V, said Aiichiro Inoue, chief scientist in Fujitsu's server group. And for floating-point processing, which is used in many mathematical calculations, its performance is 2.5 times that of Sparc64 V.

The chip measures 420 square millimeters, has 540 million transistors, will run at 2.4GHz and will consume a maximum of 120 watts and more typically 80 watts, Inoue said. It also has 6MB of high-speed cache memory shared between the two cores.

The follow-on Sparc64 VII also has a shared 6MB cache, but that chip will have four cores. As with the Sparc64 VI, each core can handle two simultaneous instruction sequences, known as "threads." That chip will measure 460 square millimeters, Inoue added.

The Sparc64 chips are at the heart of a Sun-Fujitsu collaboration called the Advanced Product Line. The servers from that collaboration are now set to arrive in early 2007, later than initially projected.

Under Niagara's hood
The Niagara processor takes multiple cores and threads to an extreme among mainstream central processors. The first generation has eight cores, each able to process four threads simultaneously. Niagara 2 has eight cores that each can run eight threads.

Sun likes to measure Niagara performance in terms of "throughput"--the amount of work performed in aggregate. The chip family is designed to run many tasks simultaneously, but a single thread won't run as fast as on conventional processor designs.

For integer tasks, the throughput is doubled on Niagara 2 compared with its predecessor, said Robert Golla, a principal architect at Sun. Throughput per watt of power consumed also is doubled, he said.

Single-thread performance improves, too, by a factor of 1.4 on integer processing and by a more dramatic factor of 5 on floating-point processing. Floating-point throughput has been boosted by a factor of 10.

The floating-point improvements are expected: Each Niagara 2 core has its own floating-point execution unit, while Niagara 1 had a single unit shared among all eight cores.

The Sparc64 V and UltraSparc TI are built with manufacturing processes that can create electronics elements measuring 90 nanometers. Their successors use a 65-nanometer process, letting more circuitry be squeezed onto the same chip. A nanometer is a billionth of a meter.

Sun considered making Niagara 2 a 16-core model, but determined that adding more threads was a more economical use of silicon chip real estate. "Doubling threads is more area-efficient than doubling cores," Golla said.