Over at Admin HPC, Dell’s Jeff Layton writes that memory bandwidth is key to optimizing application performance and that the Stream benchnmark is great way to get in there and measure it.
In the short history of memory bandwidth in Intel processors over the last six years, with close attention paid to memory bandwidth per core (because one likes to use all cores available), you could see that memory bandwidth per core varied with the “tick-tock” model. In general, the memory bandwidth trend is upward (i.e., more memory bandwidth per core over time), but not always. As a consequence, several ISV companies have recommend that their customers not use all of the cores on their processors, increasing the memory bandwidth per core used and presumably making overall performance better. Additionally, you should examine the effect on the overall performance per dollar or the performance per node to ascertain whether you have created a better system.
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