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A Three-Way AMD Opteron Server

Posted by kdawson on from the one-hop dept.

Abdul tips a thin little review up at The Inquirer of the Themis Slice. "The Slice is a three socket Opteron machine with two PCIe slots and two Infiniband 4x ports... Why would you want three sockets rather than four? Easy, latency. Any CPU in a 3S system is one hop away from any other CPU. In a 4S system, you can be two hops away. This adds latency, and more importantly, you take a big hit on cache coherency latency. This kills performance."

4 of 137 comments (clear)

  1. Re:hard to justify by pimpimpim · · Score: 2, Insightful
    tell her it will mean less hops in general, and she might be fine with it.

    (sorry about this)

    --
    molmod.com - computing tips from a molecular modeling
  2. think three-dimensional by Anonymous Coward · · Score: 1, Insightful

    Any CPU in a 3S system is one hop away from any other CPU. In a 4S system, you can be two hops away. This adds latency, ...

    How about a tetrahedron for four CPUs?
  3. Re:Weird by rrhal · · Score: 5, Insightful

               x
              /|\
             / | \
            /  x  \
           / .   . \
          x---------x

    --
    All generalizations are false, including this one. Mark Twain
  4. Re:CoProcessors? by DigiShaman · · Score: 2, Insightful

    That's why we have buses to open up expansion possibilities.

    For example, we have NIC chips that offload TX checksum processing, Audio accelerators (Creative X-Fi), 3D GPU cards (nVidia and ATI cards), and physic cards (ASUS brand AGEIA card). The only reason you want a dedicated socket is for extremely fast and wide IO to RAM. So far, only the GPU has come close to needing that but hanging just fine with the PCI Express interface.

    --
    Life is not for the lazy.