Phenom FX From AMD

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But AMD chose to build a single chip with four cores, which the company believes will result in better performance because information will not have to leave one core to visit its neighbor. It's the same debate over an integrated memory controller and point-to-point links that propelled AMD's Opteron and Athlon 64 chips to prominence: Cores that are directly linked offer better performance than cores that have to exchange information by leaving the chip. Intel contends that by improving the speed and performance of its cache memory and the front-side bus--that off-chip bridge between cores--it can offer excellent performance and sidestep manufacturing concerns. Because AMD has yet to deliver its quad-core chips, the debate is mostly aesthetic, but it could become an important distinction if Barcelona and the Phenom chips open a significant performance advantage over Intel's currently shipping quad-core processors later this year.