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

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edavid3001

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?
From what I gather there may be a performance hit if I enable this. Is
Click to expand...
that accurate?
 
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?
Click to expand...

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.
 
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?
Click to expand...

<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
 
from the said:
<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.
Click to expand...

*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.
 
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
 
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