PowerMac Processors

Discussion in 'Macintosh Computers' started by Don Cherry, Dec 24, 2004.

  1. macrumors newbie

    Dec 24, 2004
    Long Island, NY
    What is the difference between, let's say a 1.8GHZ single and Dual processor, besides the obvious?

    A Dual 1.8, is that two 900MHZ processors or two 1.8GHZ?

    What is the performance gap between these?
  2. macrumors G5

    Sun Baked

    May 19, 2002
    The SP PowerMac is a iMac in a PowerMac case -- so the single processor chipset (U3-Lite+Shasta) is the consumer chipset with the FSB running at a third of the CPU clock (600MHz.)

    The DP PowerMac has the dual CPU capable XServe/PowerMac chipset (U3H+K2+PCI-X Tunnel) run their FSB at 1/2 the 1.8 (900MHz) -- in addition the 2.0/2.5 have a faster HT bus and HT PCI-X Tunnel that the DP 1.8 doesn't include.

    The DP are basically twice as fast as the SP machines that take advantage of SMP -- and faster than the SP machines that don't because the OS will split threads between the two CPUs, so an monolithic app that hogs a CPU won't bring everything else to a crawl.

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