AMD - Changing Default FSB

[Dulanic]

Anywhere I can find info to either short pins or paint bridges to change the default FSB of my CPU from 133 to 166?

 

[MDE]

To change the bus speed you either set a jumper or a BIOS setting. To change the default multiplier or voltage try http://www.ocinside.de/go_e.html?/html/workshop/pinmod/amd_pinmod.html

 

[Dulanic]

I know for most MBs you can set jumper or change it in BIOS... thats not really the question. Im asking how to change the default FSB for the CPU... that link you gave does multiplier voltage etc... but not FSB.

 

[Dulanic]

Seems I found the answer.... bridge the 3rd bridge on L12 I was told.

 

[Boonesmi]

im curious why you would need to change the default fsb?

i thought fsb setting was handled totally by the motherboard (without cpu input) and i thought it needed to be manually set, either with jumpers or in bios

 

[johncar]

Originally posted by: Boonesmi

i thought fsb setting was handled totally by the motherboard (without cpu input) and i thought it needed to be manually set, either with jumpers or in bios

AMD furnishes a 2 bit HI/LO signal/s code for default System Clock via 1st and 3rd L12 bridges that mobo/bios "may" use to set the CPU's default System Clock. Not automatically executed as mobo components execute, CPU just sends the "signals". So execution depends on the particular mobo.
<a href="http://www.beachlink.com/candjac/index.htm">
http://www.beachlink.com/candjac/index.htm</A>
Link to FSB_Sense article for all details/circuits.
John C.

 

[Boonesmi]

fixed the link from above

and still wondering why you would need/want to change it
are their any boards that dont let you manually set the fsb speed?

 

[x-kid]

well there is this theroy that if you change the default fsb of the cpu like if it's a 133 and you change the default to 166, and if it's a 166 and you change the defualt to 133 then you'll be able to get a hight fsb. I've seen so many people do this and they are getting there fsb on average like 20mhz higher. here are some links that talk about it and show you how to do it:


Link1
Link2
Link3

 

[Dulanic]

Originally posted by: johncar

Originally posted by: Boonesmi

i thought fsb setting was handled totally by the motherboard (without cpu input) and i thought it needed to be manually set, either with jumpers or in bios

AMD furnishes a 2 bit HI/LO signal/s code for default System Clock via 1st and 3rd L12 bridges that mobo/bios "may" use to set the CPU's default System Clock. Not automatically executed as mobo components execute, CPU just sends the "signals". So execution depends on the particular mobo.
<a href="http://www.beachlink.com/candjac/index.htm">
http://www.beachlink.com/candjac/index.htm</A>
Link to FSB_Sense article for all details/circuits.
John C.

Ya unfortunetely this is for the T-Bred only, and Im trying to do this to a palo. And ZeroCustom explains it well, plus I just wanna do it to do it.

 

[Boonesmi]

i dont mean to sound rude (i actually think its kinda funny)

but after reading those threads listed above, and some other threads linked to from the 1st ones.. and with basic understanding of fsb and multiplier it makes no sense

the "theory" refered to above is pretty off the wall, and very very little chance that is has any validity (no idea if i spelled that right )


true you can reach a higher overclock if you are limited by the 12.5x multipier (then just raise the fsb and you can use lower multiplier) but that has nothing to do with "default" fsb




if i was guessing i would say its something like when someone first got the new cpu they overclocked and found the cpu's limit (or fsb, or memory, or etc limit) and then after running the cpu for awhile they do the mod and then find it can overclock higher... the problem is that after a cpu has been run for awhile it doesnt always overclock the same as when it was new (sometimes it can run faster, sometimes slower)

 

[johncar]

Originally posted by: Boonesmi
i dont mean to sound rude (i actually think its kinda funny)

but after reading those threads listed above, and some other threads linked to from the 1st ones.. and with basic understanding of fsb and multiplier it makes no sense

the "theory" refered to above is pretty off the wall, and very very little chance that is has any validity

There is no "theory", it just seems to work, and has to believable as dozens of people have reported so on systems that surely have been "burned in".

We'd guess that the "different FSB_Sense setting" causes the mobo/bios/Northbridge?? to make some "unknown different setting related to latency/wait states/timing during boot", or whenever that code is interrogated, that enables a higher System Clock set later manually in the bios. Too many successes to not believe that "something" happens.
John C.

 

[Boonesmi]

Too many successes to not believe that "something" happens

most of the "sucesses" i read didnt seem valid at all...

 

[MatthewF01]

maybe you guys can offer me a little insight.


im running a Chaintech 7NJS Nforce2 motherboard with one stick of Corsair 3200c2 512MB.

Up until the end of last week, I had an 1800+ TbredA running at 217*8.5.

Then I replaced it with a Barton 2500+. Problem is that I am only able to hit 180 and still get into Windows. Seems anything higher will not allow Windows to kick in...
Its really pissing me off because my other chip did it easy and im wasting my 3200 ram...


Do you think this mod might help me out? Any reasons why switching chips to the 2500+ would give me this issue in the first place? I mean, the fact that its a 166fsb chip is the only difference i would think would play some part in this.



And another thing, im not getting anywhere near the speeds people are saying while using DEFAULT voltage everyone else is, wtf is going on here?
so far im very pissed off and disappointed until someone can help me figure out my issue