Make the Right Choices

  • Pick the Right CPU
    There are a number of choices of CPU including: Intel Celeron, PII, PIII, PIV, Itanium; AMD Athlon, Thunderbird, Duron; Compaq Alpha

    Celeron is limited by 66 MHZ FSB.
    PIII can have 100 or 133 MHz FSB.
    PIV is new and currently expensive.
    Itanium is soon to be available.
    Athlon has performed well for me and 200 MHz FSB may actually be useful.
    Alpha has great performance, but is expensive.

  • Pick the Right Memory
    There are currently several memory types available for different processors. They include PC100, PC133, Rambus, Double Data Rate (DDR), which is also known as PC1600 or PC 2100.

    PC100 and PC133 are fairly mature at this stage and there is little difference in price.
    Rambus was quite expensive at introduction, but has recently decreased quite a bit. Intel was pushing it hard, but it seems to have lost in the marketplace.
    DDR is just now coming to market (Micron), but it does not carry too much of a premium. Issue here is finding a suitable motherboard. Memory often has a sweet spot. Highest density often is expensive. Pick the right amount of memory for your problems.

  • Pick the Right Motherboard
    Motherboard must be matched to processor and memory. The support chip can have an important impact on performance.
    Motherboard determines number of processors per node. Can your problem benefit from multiple processors?
    Motherboard also determines the speed and width of the PCI bus. If you use Myrinet, for example, you should benefit from having a 64-bit 66 MHz PCI bus, which has four times the bandwidth of the minimal standard.

  • Pick the Right Network and Software
    FastEthernet is the commodity network. Other choices such a Myrinet, Giganet, Gigabit Ethernet, Quadrics QSnet and SCI from Dolphin/Scali have higher performance, but are quite expensive compared to FastEthernet. Because of the big jump in price and performance, it is necessary to make sure the system maintains balance between CPU and network.

    Under FastEthernet MVIA and GAMMA software may improve message passing performance. I have recently tried VMI under Myrinet and found it to be superior to running under standard GM (Myrinet supplied) driver.





Single Node Performance (next slide)

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