AMD surprised everyone last year when it announced its plans to introduce triple-core Phenom desktop processors. The company justified the move by saying triple-core offerings would help "stimulate broader multi-core adoption," and it added that its native quad-core architecture placed it in a "unique position" to offer such chips—and to distinguish itself from Intel.
Intel hasn't announced a riposte to the move yet, but according to an Intel presentation inadvertently leaked by Sun and nabbed by Ace's Hardware forum members, the company also has plans to tread where its competitor can't. The presentation, which Sun has now taken down, says Intel will roll out a six-core, Penryn-based Dunnington server and workstation processor in the second half of this year. Where existing 45nm quad-core Xeons have two Penryn dual-core dies side-by-side on the same package, Dunnington will have three. Intel will also toss in a 16MB pool of L3 cache that will be shared between all six cores.
Apparently, Dunnington will communicate through a 1066MHz front-side bus, and it will have a thermal envelope of 130W or less. The slide touting the chip also claims it will be pin-compatible with Tigerton—Intel's existing quad-core, 4P-capable, Core-based Xeon that fits into 604-pin mPGA sockets.
Juicy tidbits about Dunnington aren't all the leaked presentation has to reveal, though. The slides include some performance projections for both Nehalem, Intel's next-generation quad- and eight-core chip, and Shanghai, the 45nm shrink of AMD's quad-core Barcelona. Intel's performance chart only shows how the chips perform in SPEC int_rate and SPEC fp_rate benchmarks compared to a baseline dual-core Xeon E5160, but George Ou from ZDNet has extrapolated some actual numbers based on Intel's published scores for the E5160. Those numbers ought to be taken with a grain of salt, but they are interesting nonetheless, and they haven't been pulled by Sun.
According to Ou's extrapolated data, Intel expects a 2.8GHz Shanghai processor from AMD to have an int_rate score of 121 and an fp_rate score of 123, both higher than the respective 80 and 122 scores of its 3.2GHz quad-core Xeon X5482. However, Ou says Intel also expects a Nehalem chip with undisclosed specifications to score 176 in int_rate and 163 in fp_rate, wiping the floor with the Shanghai part. Intel's slide doesn't say whether the Nehalem chip in question is a quad- or eight-core model or how fast it actually runs, though.