[Beowulf] Nehalem memory configs

Jason Clinton jclinton at advancedclustering.com
Sun Apr 12 20:53:59 PDT 2009


On Sun, Apr 12, 2009 at 10:43 PM, Jason Clinton <
jclinton at advancedclustering.com> wrote:

> No, it does not degrade performance as long as the CAS latencies of both
> DIMM types are identical and you would not get a clock-down by using that
> quantity of RAM ranks. We have been able to attain Intel's reported, magical
> 35GB/s number using ICC. GCC 4.3 is around 31GB/s. (At 1333MHz.)
>

I should qualify those numbers a little: when using any quantity of RAM
exceeding 1 DIMM per channel, they clock down to 1066MHz, and benchmark at
33 GB/s w/ ICC and 29 GB/s with GCC 4.3. It doesn't matter if they are
different sizes or not. The 35GB/s number is for single-populated memory
configurations.

-- 
Jason D. Clinton, 913-643-0306
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