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Theoretical vs measured memory bandwidth of Nehalem

idata
Employee
‎11-03-2009 09:30 AM
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Hi,

What is the reason why the theoretical memory bandwidth of a Nehalem CPU (1333 * 3 channels * 64 bits / (8bits/byte) = 32GB/s per socket) is not similar to the measured bandwidth using the STREAM benchmark which is around 17GB/s per socket, or 37GB/s or so for a two-socket motherboard? I thought STREAM should give pretty close to the maximum throughput possible.

How can you calculate the memory bandwidth so it's closer to the observed result? I.e. what am I not taking into account.

Thanks,

Milos

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Daniel_O_Intel
Employee
‎11-04-2009 05:05 PM
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Not sure. This community is mostly for server boards and storage - have you tried asking this over in the processor community http://communities.intel.com/community/tech/processors ?

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