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Spread Spectrum?

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February 12, 2006 3:46:28 PM

I was browsing through my BIOS this morning just to get an idea of all the options and stuff my new DFI LP UT NF4 DR SLI Expert has to offer before I go to overclock (probably not for a month or so, wanna get use to it on stock speeds so I notice the difference when I do OC). There were some new ones I came across that I didn't see in the BIOS of my last PC so I don't know what they were or what/how they effect performance.

They were CPU Spread Spectrum, PCIe Spread Spectrum, and SATA Spread Spectrum and they were all set to Disable by default. The instructions for the mobo didn't help as all they said "You can set this to Enabled or Disabled"

So anyone know exactly what these are/do and how it effects performance and whether or not I should turn them on?

Thanks in advance

More about : spread spectrum

February 12, 2006 4:05:41 PM

They have to do with interference issues with surrounding equipment. I would just leave them disabled.
February 12, 2006 4:22:14 PM

Luminaries is right, you can find more info in THG article:http://www.tomshardware.com/2005/09/22/bios_for_beginne...
Quote:
FSB Spread Spectrum : Disabled. This feature helps systems pass European electromagnetic interference (EMI) tests. It accomplishes this by constantly varying, ever so slightly, the frequency of the Front Side Bus (FSB). Be warned that enabling this feature with large values can result in Internet connection disruption, as well as stability problems if you overclock your system.

AGP Spread Spectrum : Disabled. The description above applies here as well, except that this is for modulating the frequency of the Advanced Graphics Port (AGP) interface.

Also see http://www.tomshardware.com/2006/01/04/bios_from_a_to_z...
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February 12, 2006 4:41:07 PM

my mobo gives the options of Disabled and then about 5 dif settings from -0.5% to -1%... made me really wonder what it was about. We have a problem playing a radio in the room when my computer is on... I wonder if that would change anything... :? of course, it makes not difference whether I overclock or not, so it prob wouldn't do anything for my problem.
February 12, 2006 5:44:23 PM

You can find more about spread spectrum at http://en.wikipedia.org/wiki/Spread_spectrum

Try playing with the settings on your motherboard and see if the interference go away.
Is your radio AM or FM? Is it a good quality radio? Have you tryed moving the radio in the room?

You might have a bad fan in your computer and that could cause interference in your radio also.
February 12, 2006 5:46:58 PM

Keep in mind though that enabling spread sprectrum actually hurts performance. I don't know how much exactly because I've never tested it but, articles I've read have shown that it does hurt.
February 12, 2006 5:56:07 PM

that's because it spreads down, not up....

and, the radio is an AM radio, there is some minor interference on FM, but when we try AM, it just doesn't work, you can even hear the mouse moving on the screen 8O... and yes, it's a cheap radio, that could be the problem.
February 12, 2006 7:24:59 PM

Quote:
Luminaries is right, you can find more info in THG article:http://www.tomshardware.com/2005/09/22/bios_for_beginne...
Quote:
FSB Spread Spectrum : Disabled. This feature helps systems pass European electromagnetic interference (EMI) tests. It accomplishes this by constantly varying, ever so slightly, the frequency of the Front Side Bus (FSB). Be warned that enabling this feature with large values can result in Internet connection disruption, as well as stability problems if you overclock your system.

AGP Spread Spectrum : Disabled. The description above applies here as well, except that this is for modulating the frequency of the Advanced Graphics Port (AGP) interface.

Also see http://www.tomshardware.com/2006/01/04/bios_from_a_to_z...


Awesome, thx. I had forgot about that article, very helpful. Can't wait to get home and tune my bios some more
February 12, 2006 7:47:31 PM

Thanks for the insight wusy. I never did really follow up on it cause I never use it.
!