Printable View
Just upgraded my bios to 1007 from asus. Noticed two settings that have no information about them in the manual or in the bios. What do these do and should what should I set them to?
FSB Spread Spectrum
with options of Disabled, 0.50%, 1.00%
AGP Spread Spectrum
with options of Disabled, 0.50%, 1.00%
Currently both are disabled.
Thanks,
Eric
Perhaps this will help:
http://www.tomshardware.com/howto/20...tuning-17.html
or perhaps it won't ! :pQuote:
Originally Posted by TripleRLtd
Its all about 'skew' ... 'Tom' shows a distinct lack of grasp on the subject, but I of course, 'knowing all things' (this is a running joke with me & tripleR, for anyone concerned about my 'conceit' ;)) will endeavour to explain.
'Spread spectrum' of any variety, relates to how long timings of signals along any bus are allowed to be either 'early' or 'late', it therefore can adjust any BIOS timings to allow for this, think of it like a railway & lots of trains running up & down one single line, so only one train on any one section at once otherwise you get collisions & your trains crash (loose data), so its all very well if all your trains run at the same speed, you can calculate how long your train takes to get from station to station each time & set other ones off, being able to predict where all the others will be - but if you get a slow train or a fast one, all holy hell might break loose - spread spectrum settings relate to the delay or anticipation you'd have to make to stop your trains colliding.
Skew is the mismatch generated if we had lots of train tracks in parallel, as we can never 'quite' get all those tracks just exactly the same length, so even though all our trains go at the same rate if we run two trains along that system, one will always get there just a tad before or after the other - when this 'mismatch' gets too big we need to adjust the skew with a spread spectrum adjustment (Electronics now are real good at this, however historically devices weren't always that good, so the adjustment still lives on in bios in case we have anything 'iffy' floating about & start having to do all that train speed limit stuff)
But yeah you want them OFF ... we want all the trains to run on time don't we ? :grin:
eedmond, in case you can't see clearly through this explanation, this article:
http://www.e-insite.net/ednmag/archi...98/11df_04.htm
explains the principles quite well.
Tom is correct to the degree that the spread spectrum feature in motherboards is a technique of varying the clock frequency to help with EMI compliance. It's mostly used for systems in plastic cases, so can normally be left disabled. More so as Spread Spectrum can make some systems less stable, as it makes more demands on the timings mentioned by Confus-ed.
Do you not like my train ananlogy Platypus ? :(
I couldn't think of any other way without using the phrase harmonic sychronisation and starting on about pseudorandom noise (I had to look up how to spell those :D) ... anyway its electric signals getting out of whack - its all about timing, baby ! ;)
One of the best ananlogies I've seen ... ;)Quote:
Originally Posted by confus-ed