Jump to content

Spread Spectrum Clocking


Recommended Posts

Does anyone know what Spread Spectrum Clocking is, There is A jumper on my WD Raptor that enables or disabled this action. I noticed it now, as I am installing another 80 gig harddrive. I took the jumper out thinking it was required since I only had that 1 hardrive but now I realize that sata does not need to be jumpered for master/slave. Should I disabled or enable SSC? Thinks!

Share this post


Link to post
Share on other sites

FROM ADRIAN'S ROJAKPOT

 

Spread Spectrum

 

Common Options : 0.25%, 0.5%, Smart Clock, Disabled

 

Quick Review

 

This BIOS feature allows you to reduce the EMI of your motherboard by modulating the signals it generates so that the spikes are reduced to flatter curves. It achieves this by varying the frequency slightly so that the signal does not use any particular frequency for more than a moment.

 

The BIOS usually offers two levels of modulation - 0.25% or 0.5%. The greater the modulation, the greater the reduction of EMI. Therefore, if you need to significantly reduce your motherboard's EMI, a modulation of 0.5% is recommended.

 

In most conditions, frequency modulation via this feature should not cause any problems. However, system stability may be slightly compromised in certain situations. For example, this BIOS feature may cause improper functioning of timing-critical devices like clock-sensitive SCSI devices.

 

Spread Spectrum can also cause problems with overclocked systems, especially those that have been taken to extremes. Even a slight modulation of frequency may cause the processor or any other overclocked components of the system to fail, leading to very predictable consequences.

 

Therefore, it is recommended that you disable this feature if you are overclocking your system. The risk of crashing your system is not worth the reduction in EMI. Of course, if EMI reduction is important to you, enable this feature by all means. But you should reduce the clock speed a little to provide a margin of safety.

 

Some BIOSes also offer a Smart Clock option. Instead of modulating the frequency of signals over time, Smart Clock turns off the AGP, PCI and SDRAM clock signals that are not in use. Therefore, EMI can be reduced without compromising system stability. As a bonus, using Smart Clock also helps reduce power consumption. The degree of EMI and power reduction will depend on the number of empty AGP, PCI and SDRAM slots. But generally, Smart Clock won't be able to reduce EMI as effectively as simple frequency modulation.

 

With that said, it is recommended that you enable Smart Clock, instead of the 0.25% or 5% option, if the option is available to you. It allows you to reduce some EMI without any risk of compromising your computer's stability.

Share this post


Link to post
Share on other sites

  • 4 months later...

I have a valid reason for waking this thread from the dead, and if anyone can explain, please do share :)

 

I bought an eSATA/USB 2.0 enclosure for a Seagate SATA 3.0gb/s drive. When hooked up via SATA, the drive will stop responding when copying stuff to it. When hooked up via USB, it runs just fine. At first I thought perhaps the drive or enclosure were defective, but when I hooked up the drive directly to the motherboard, it formated just fine.

 

I remembered the SATA Spread Spectrum option in the bios. I enabled it, and now I have no problem writing to that external SATA drive in the SATA enclosure.

 

Any thoughts?

Share this post


Link to post
Share on other sites

First question that popped-in to my head:

 

How are the cables routed in the system? Can you take a pic?

I have a valid reason for waking this thread from the dead, and if anyone can explain, please do share :)

 

I bought an eSATA/USB 2.0 enclosure for a Seagate SATA 3.0gb/s drive. When hooked up via SATA, the drive will stop responding when copying stuff to it. When hooked up via USB, it runs just fine. At first I thought perhaps the drive or enclosure were defective, but when I hooked up the drive directly to the motherboard, it formated just fine.

 

I remembered the SATA Spread Spectrum option in the bios. I enabled it, and now I have no problem writing to that external SATA drive in the SATA enclosure.

 

Any thoughts?

Share this post


Link to post
Share on other sites

h o im confused

 

first off-- whats the diff between eSATA and regular SATA? sry to be stupid and to hijack the thread

 

and secondly: on my raptor i just removed the jumper. drive worked fine till the next day-- it stopped spinning. i think i accidentaly killed it with my force, so i rmaed it..

 

i had trouble getting wd's lifeguard to identify. plus i enabled the spread spectrum in my bios. dunno what now.

Share this post


Link to post
Share on other sites

Well, you know some of the DFI motherboards come with this little front case attachment called Frontx? One of the connections is SATA. The 1st pic shows what it looks like, and you can see it looks exactly like a standard internal SATA connector. That port is directly connected to one of the MB SATA ports. 2nd & 3rd pic show the eSATA connector (which I can only think stands for external SATA. If you notice, the eSATA doesn't have that little plastic piece shown by the blue arrow.

 

The enclosure came with a rear plate adapter with an eSATA connector outside and a standard SATA connector for the inside to connect directly to the MB. The inner cable of that plate adapter I just simply connected it to the port in the first pic, and then I attached the eSATA cable to the enclosure and to the plate adapter.

 

What I WILL end up doing though is swapping the port from the FrontX with the one from the plate adapter.

 

attachment.php?attachmentid=4034&stc=1

Share this post


Link to post
Share on other sites

eSata is not the same spec nor does it use the same cabling since eSata says it will be able to use about a 6 foot sata cable. The problem comes from shielding for eSata and eSata cables are much better shielded or "they say" they should be. As shown in pics above the eSata cabling has different indexing in order to try and keep wrong cable hook ups from happening would be my guess.

 

Almost any eSata drive that is outside the case will need eSata cables and should plug into a card edge adapter thru the rear of case usually that has adapted eSata to the internal sata spec.

 

Having seen users create sata drive errors by 'how' they routed the cables in the case> I can easily see that eSata for a distance of six feet may cause problems that using Spread Spectrum clock to the external eSata drive might help. BUT then oh my gawd how the board may well have to be clocked down. All the geewhizzes are neat and shiney and pretty and usually come with their own inherent penalties.

 

Heck back about 10 or so months ago Hitachi almost lost all their OEM sales because they were shipping drives with Spread Spectrum Clocking enabled on all their drives and they worked like crap with a bunch of OEM boards. That is why they quickly changed that feature and ALSO began to ship them with 3.0gbs turned off so there was not cause for the OEMs to drop them as a supplier. A whole lot of stuff goes on in the background that makes me steer clear as far as I can from most of the new geewhiz stuff and the some of the prices; that I am unwilling to pay.

 

RGone...

Share this post


Link to post
Share on other sites

Please sign in to comment

You will be able to leave a comment after signing in



Sign In Now
×
×
  • Create New...