Athlon II Or Phenom II: Does Your CPU Need L3 Cache?

Athlon II X4 And Phenom II X4

Our comparison utilizes two different AMD products in an effort to pinpoint the true benefit of a modern quad-core processor’s L3 cache.

On one hand, we had AMD’s new Athlon II X4 620, which is the firm’s entry-level quad-core. The Athlon II X4 620 marks the first time a quad-core product has broken under the $100 cost line, thereby introducing new levels of performance at this price point. However, the 620’s impressive performance only applies to heavily-threaded applications, and it may not apply at all times, because the Athlon II X4 does not have any L3 cache. For comparison, we also used a Phenom II X4 965.

The positioning of these two products couldn’t be more different. The Phenom II is AMD’s current Black Edition flagship model, while the little Athlon II X4 is a lower-end mainstream chip.

Still, they’re very similar inside. The Athlon II X4’s cores, including their L1 and L2 caches, are identical to the Phenom’s. AMD didn’t change cache associativity. In fact, the only real change here came when AMD switched the Athlon II X4’s cache off to be able to utilize processor dies that failed validation due to L3 issues (Ed.: Note that this is only the case for early Athlon II X4s. Moving forward, more and more of them will center on a completely different, more economical processor die).

An apples-to-apples comparison is possible by reducing the Phenom II X4’s clock speed from 3.4 GHz to only 2.6 GHz, which is the stock speed of the Athlon II X4 620.