a8n-sli-p and Spread Spectrum Clocking (SSC)

Discussion in 'Asus' started by edavid3001, Aug 12, 2005.

  1. edavid3001

    edavid3001 Guest

    I've enabled SATA II 3G/ mode and that works fine. But what about this
    option of Spread Spectrum Clocking (SSC)?

    Question #1) Does the A8N-SLI-p support this? I could find nothing
    about it in the manual or doing Google searches.

    Question #2) If it does support this, would I want to enable SSC?
    that accurate?
     
    edavid3001, Aug 12, 2005
    #1
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  2. I have not seen such an option in the BIOS. Generally the only purpose
    of spread-spectrum clocking is to reduce RF interference levels, so it
    is mainly important to system manufacturers trying to get FCC certification.
     
    Robert Hancock, Aug 13, 2005
    #2
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  3. edavid3001

    Ed Guest

    <paste> (found this somewhere, years ago)
    When the motherboard's clock generator pulses, the extreme values
    (spikes) of the pulses creates EMI (Electromagnetic Interference). The
    Spread Spectrum function reduces the EMI generated by modulating the
    pulses so that the spikes of the pulses are reduced to flatter curves.
    It does so by varying the frequency so that it doesn't use any
    particular frequency for more than a moment. This reduces interference
    problems with other electronics in the area. However, while enabling
    Spread Spectrum decreases EMI, system stability and performance may be
    slightly compromised. This may be especially true with timing critical
    devices like clock-sensitive SCSI devices.
    </paste>

    So I guess if you had a radio or TV close to the PC and they were
    picking up noise you'd enable it. I never enable it and systems are all
    rock solid 24/7.

    Ed
     
    Ed, Aug 13, 2005
    #3
  4. *cynical answer*
    Basically it helps them pass the EMI tests of the FCC et. al. Once
    they've passed the tests, they really don't expect anyone to ever turn
    it on.
     
    GSV Three Minds in a Can, Aug 13, 2005
    #4
  5. edavid3001

    edavid3001 Guest

    Okay, thanks. Hitachi ships SATA II harddrives in SATA I mode. I've
    gone into the harddrive settings (not motherboard settings) to enable
    SATA II and I had to select between enabling or disabling Spread
    Spectrum Clocking before I could save the SATA settings.

    Having never heard of it, I wasn't sure what I should select. There
    was not a default.

    Now I know. Thank you.

    Edwin
     
    edavid3001, Aug 15, 2005
    #5
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