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FSB, Bus speed, memory speed??!!

Discussion in 'Hardware' started by esara, Apr 7, 2004.

  1. esara

    esara Guest

    I have a problem to understand what is the relation between FSB and
    BUS speed and Memory speed??

    1)What is FSB? is it a physical bus? is it in the motherboard?? if
    yes, why CPU manufacturing company say for example AMD 2.4 with FSB
    133 Mhz, does that mean FSB is part of the CPU architecture?? IF yes
    it is part of the CPU, should FSB match the BUS speed of the mother
    board to get fast computer??

    2) What does the BUS speed mean?? does it mean the speed of the
    motherboard buses?? does it have any relation with FSB??

    3) How about Memory rate or speed?? does that mean the speed of the
    bus inside the memory in other words, the speed that is used to
    transfer data inside the memory? How this speed related to FSB or BUS

    Any help would be very much appreciated. Thanks
    esara, Apr 7, 2004
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  2. esara

    jamotto Guest

    Since I can not draw at all. Please refer to the following link
    about half way down the page is a picture labeled "Blockdiagram" I'll
    be using this as my picture.
    now the questions

    1.)What is the FSB? In the diagram at the top you will see AMD Athlon
    XP Processor then a line to a chip called "KT600 North bridge" the
    line represents the FSB as stated can run at 400/333/266MHz.

    2.)What is a chipset? in the picture the "KT600 North Bridge" and the
    "VT8237 South Bridge" are the chipset, VIA is using a two chip design
    others may use just one.

    3.)What does it do? The chipset can be thought of as an interface for
    the processor and for that matter just about any device you hook up to
    the chipset to communicate with each other. for example the processor
    can transfer data to your memory by first crossing the FSB to the
    first chip in the chipset "KT600 North Bridge" which routes it to the
    memory to the left at speeds of either 400/333/266 depending on what
    type of memory you have running.
    or if say you just started a program it will load itself into memory.
    It does this moving data from your harddrive(represented as the yellow
    rectangles just below "2D/3D Graphics") to the South Bridge then to
    the North Bridge then to the memory.

    These are examples of theoretical memory speeds
    type speed*(2 for DDR) transfer rate from memory to the
    PC3200= (200MHz * 2) * 8bytes = 3200MB/s
    PC2700= (166MHz * 2) * 8bytes = 2656MB/s or 2700 rounded up
    PC2100= (133MHz * 2) * 8bytes = 2128MB/s or 2100 rounded down
    PC1600= (100MHz * 2) * 8bytes = 1600MB/s

    I hope this answers all your questions.
    jamotto, Apr 8, 2004
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