Memory subsystem performance

Before we get into application performance, here's a quick look at the memory subsystems of the X4 965 and its competition. The graph above shows the bandwidth delivered at each stage of the memory hierarchy. Superficially, the X4 965 isn't too different from its closest rival, the Core 2 Quad Q9550. The Q9550's L1 cache tends to deliver higher bandwidth at block sizes below 256KB, but the Phenom II's cache hierarchy achieves higher throughput at intermediate block sizes—and its integrated memory controller delivers the goods at the largest block sizes, where main memory bandwidth comes into play.

Here's a closer look at the largest block size. The X4 965's dual channels of DDR3 memory perform nicely, while the Q9550's bandwidth is limited by its front-side bus. Then again, Intel has incorporated a triple-channel memory controller into the Core i7, and wow.

Integrated memory controllers reduce the latency caused by chip-to-chip communication, and so the Phenoms and Core i7s occupy the top rungs here. The Phenom II X4 965 slots in right where one would expect.