FSB

Discussion in 'Hardware' started by keithmoon, Sep 10, 2009.

  1. keithmoon

    keithmoon Byte Poster

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    Hi all,

    Reading some A+ material this morning.
    Just to confirm i have understodd this correctly, even if your cpu runs at say 3.2 GHZ it will still be limited to the speed of the FSB supplying the I/O controller??? for example as slow as 800 MHZ.

    thanks
     
  2. greenbrucelee
    Highly Decorated Member Award

    greenbrucelee Zettabyte Poster

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    The frequency at which a CPU works is determined by applying a clock multiplier to the FSB speed.

    For example, a processor running at 3200 MHz might be using a 400 MHz FSB. This means there is an internal clock multiplier setting (also called bus/core ratio) of 8. That is, the CPU is set to run at 8 times the frequency of the front side bus: 400 MHz × 8 = 3200 MHz. By varying either the FSB or the multiplier, different CPU speeds can be achieved

    My cpu is runing at 3.91GHz which amounts to the multiplier being set at 9 and the fronside bus being set at 433
     
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  3. keithmoon

    keithmoon Byte Poster

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    ahhhhhhhhhhh i see , so by overclocking your going against the reccomended multiplyer? for example if your cpu was supposed to be running at 4.0 GHZ and your FSB speed was 500 MHZ you would have a multiplyer of 8 running? but if you wanted it to run faster than 4.0 GHZ you would crank up the multiplyer?
    am i right in thinking these multiplyer settings are found in the bios?

    Thanks green bruce lee for the quick reply
     
  4. greenbrucelee
    Highly Decorated Member Award

    greenbrucelee Zettabyte Poster

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    You can't go over the highest multiplier but you can go over the rated FSB. Some people drop their multiplier when overclocking and raise the FSB more.

    Some AGP and PCI cards have their own clocks so they don't reply on the cpu.

    I normally keep the cpu at its highest multiplier in my case is 9 then I raise the FSB. The FSB also affects the ram speed too.

    If you look in your bios in cpu configuration section you will most likely see a setting called intel speedstep and/or C1E this automatically changes the multiplier with in that cpus settings, so for example my cpu is core 2 duo 3GHz 3000.5MHz when I am looking at the internet or not doing much Intel speed step drops the multiplier to run the cpu at a slower speed to save power. So when I am at stock my FSB is 333 but it can be as low as x 6 or as high as x 9. I usually disable all that and run at full whack :)

    PS if your interested in overclocking remember it has its risks and voids your cpu warranty
     
    Last edited: Sep 10, 2009
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  5. keithmoon

    keithmoon Byte Poster

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    thanks mate sorted8)
     
  6. supernova

    supernova Gigabyte Poster

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    I you have any more queries take a look at this thread


    http://www.certforums.co.uk/forums/thread27783.html


    there's also a useful external link mentioned there.
     
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  7. keithmoon

    keithmoon Byte Poster

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    thanks for the link :)

    Just while were talking about FSB speed. I was reading about memory and SDRAM, am I correct in saying that SDRAM runs at the same speed as the FSB it being synchronous?
     
  8. keithmoon

    keithmoon Byte Poster

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    can someone explain my output please?
     

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    Last edited: Sep 15, 2009
  9. supernova

    supernova Gigabyte Poster

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    HT Link = HyperTransport

    effectively a FSB replacement , things are different i haven't yet covered this in any real detail it was outside the scope of the A+ when i took it, it may have been added to the objectives i dont know
     
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  10. supernova

    supernova Gigabyte Poster

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  11. keithmoon

    keithmoon Byte Poster

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    cheers mate
     

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