noober FSB question

I've got an athlon 1.2 ghz processor, 2 sticks of pc133 256mb ram and am trying to change my FSB from 100mhz to 133mhz. When i change the settings on the motherboard i can't start my comp back up. It will start to run but the monitor won't come on. Any ideas of what i'm doing wrong or how i need to get this to work? Thanks

Hmm...

Well first, welcome to the forums.

More information would be a big help.
What motherboard are you using? What brand of Ram? and any other system specs you think might be relevant.
Is the chip a 200mhz or 266mhz version?

We'll be able to answer your question with more certainty with more info.

Blue

Hmmm i'm not really sure what most of it is, got the ram from a buddy who bought it at best buy, the motherboard is a chaintech with a via chipset, until i find my manual that's all i know (recently moved and i don't know where alot of stuff is). I don't know if it matters but i'm using a voodoo 4 4500 and a soundblaster live mp3+. That's all i can think of, i feel pretty stupid for not finding out what kind of ram it was. Thank you for the help though it's more than i've got from anywhere else .

Maybe you should have asked this question in the AMD CPU section or the AMD motherboards. Anyway, if your board as a fsb of 100, thats why you cant do 133fsb. Have you tried lower fsb? Try 105Mhz and see if it boots up. If it does, it means that your mobo has a fsb of 100Mhz.

hmmm, you would think the board would be able to handle it since i bought it as a package with the processor and was supposed to get 1.2 ghz out of it. Anyway thanks for the help, sorry if i posted this in the wrong section, wasn't too sure where it was supposed to go.

hola tappwin, welcome to the forums!

what you may need to check for is a jumper on your motherboard that changes from 100 to 133mhz FSB. each particular mobo is different, as some are completely changed in the BIOS.

i dont know if this is the case with your system, but as with mine and several others, there are actually TWO 133mhz FSB settings.

one is 133mhz fsb with a 44mhz pci, the other is a 133mhz fsb with a 33mhz pci. the difference is...

your PCI cards, AGP card, hard drives, etc are all based on a divisor of your FSB. so on a 100mhz fsb motherboard, there is a pci divisor that is 1/3 (making the pci bus run correctly at 33mhz). if you take a 100mhz fsb and overclock it to 133mhz, then you have in fact overclocked the rest of your computer (because of the 1/3 divisor).

on a 133mhz fsb motherboard, there is a 1/4 divisor, making the pci run correctly at 33mhz.

if you could find the model numer of your motherboard (or better yet, the manual), we should be able to figure out how to set the motherboard to run at 133mhz with a 1/4 divisor (provided it's capable of that).

my guess is that you may have improperly set the fsb to 133mhz without putting the PCI/AGP/IDE back to their proper speeds.

anyhow, good luck, and keep us posted!

Watch your computer when is POSTs. If the chip registers as a 1.2GHz T-Bird, then the problem is the chip is a 200FSB version...which means it was meant to run with a FSB of 100 (which the chip doubles to 200), running it at 133 will make the chip run at 266, which is too much.

Thank you alot for all the help, this is the best board I've ever seen, no flames no whiners or griefers, just lots of helpfull ppl .

On to my prob I think my manual may be in that black hole my girl friend calls her room, but i did find a sticker with the mobo's layout mysteriously stuck to the inside of my case lol.

It doesn't have the make or model, but in the upper right corner it has P/N :9577018003 and Code: 7CTAIA_Label V.3_E which prbly doesn't mean anything lol. But it does have a listing for the CPU bus frequency selector and a diagram of the switch positions for both 100 and 133mhz. That is the only one that i can find, at least unless i can find that manual. anyway i'll keep trying till i fry something

Thanks alot for all the help

well...

i found chaintech's website, and the closest models i could find on their site were the 7AIA and 7AIA5.

here's the link to their motherboard selector page chaintech

those two mb's show that you have either a via kt133 or kt133a chipset, which coincides with what you said (via chipset). since you say you saw a sticker with a selector between 100/133mhz fsb, that makes me believe it may be the 7AIA5, which is the only one capable of both 100/133 mhz fsb.

go ahead and take a look at the 7AIA5 picture and let me know if that looks like your motherboard or not. for now, i'm going to assume that this is the correct one and see if i can troubleshoot it from here.

well, unfortunately they dont have an online support database, or any online manuals...

what i would do if i were in your shoes:

only plug in the video card, ONE stick of memory (make sure it's in dimm slot 1, which should be marked by the slot on the motherboard), the processor (with the heatsink/fan plugged in of course!), monitor, keyboard.

dont have any other hard drives, floppy, cd, etc plugged in until you can get the computer to post at 133mhz. this will narrow down the area you have to search for problems at.

change via jumper to 133mhz fsb. and turn the computer on... see if you can get it to post with the minimal items plugged in.

if you cannot, turn the computer off, then restart while holding down the insert key (keep holding it down, this will reset your BIOS).

if it still will not post, the next two things i would check is to see what version bios you have (will have to set it back to 100mhz fsb to see). if you have an updated bios, the other thing to check would be to see if your processor and memory are actually designed to run at 133mhz.

one last thing, you may be able to test the memory by entering the bios (with fsb at 100mhz) and check for a setting that is along the lines of "ram=fsb" that can be changed on some computers to the setting "ram = fsb+33mhz". that would make your fsb stay at 100mhz, but your ram run at 133mhz (by doing this you can determine if the ram is or is not your problem).

chuckchippie said:

If the chip registers as a 1.2GHz T-Bird, then the problem is the chip is a 200FSB version...which means it was meant to run with a FSB of 100 (which the chip doubles to 200), running it at 133 will make the chip run at 266, which is too much.

Click to expand...

Not true. My system doesnt think so anyway.

Take the Northbridge fan off & take a look at the codes on the chip jus to make sure it is a KT133Achipset. The older KT133 will not want to run at anything higher than 115FSB if your lucky enough to reach that high.

I'll try those today and see what happens, i was thinking that they may have packaged a 900mhz chip in the 1.2ghz box but i don't know how to check that for sure.

ok from the chaintech website it looks like a 7AIA, which on the website says it supports FSB 200, and i clicked on the literature link and it's specs say FSB 100/133 & 100 DDR

Tappwin said:

ok from the chaintech website it looks like a 7AIA, which on the website says it supports FSB 200, and i clicked on the literature link and it's specs say FSB 100/133 & 100 DDR

Click to expand...

i think that pdf file has a typo on it... according to via themselves, the kt133 can only support 100mhz fsb (200mhz ddr fsb) but that it also supports 133mhz RAM (the fsb still stays at 100mhz).

here's the kt133 link via

if you think you have a 900mhz cpu, you can check by looking at the code on the cpu core itself. to do this you would need to remove the heatsink (be careful! and make sure to NOT turn on the computer without properly replacing the heatsink, as it will toast the cpu).

to check which motherboard you have, you can look for the chipset indicator (on the northbridge) it should say VIA KT133 or VIA KT133A. (the northbridge is the big black square in the middle of the motherboard that has VIA on it according to the picture i see)

if you do in fact have a KT133 and not a KT133A chipset, your only option is to attempt to run the cpu at 100mhz fsb, with a 12x multiplyer (if the mobo will let you go that high). that, or else get a new motherboard that supports 133FSB.

hope this helps, and good luck!

Ok in the middle of the board is a green thing with 3 lines forming a figure 8 on it. The only thing like you described that said via on it was in the lower right corner. it says VT82C686A
0102CG Taiwan
1DC4N6781

I know what the Taiwan means but that's it lol

Thanks alot for the help

Ok i found something that could help but before i play with i'm wondering if this could be bad for my system.

In the bios i looked under CPU host/pci clock and put the settings a bit higher which increased the speed of my processor, will maxing this out to 120/40mhz be a bad idea? or should i leave it or go for a slightly higher but not the highest setting

thanks

If i'm not mistaken that is the setting for the divider. The first number is your fsb, the second is your pci bus.
The pci bus is meant to run at 33mhz, when you up the fsb it up the pci bus moving it out of spec.
That looks like the divider is set to 1/3, if that is the highest setting your mb supports that is your problem most likely.
Before you changed the settings I assume it was set to 100/33?
If you can set it to 133/33 then you should be ok, if 1/3 of the fsb is the best it can do then that may be why it won't run at 133.
Most pci cards don't mind running a little out of spec but setting the bus to 133 with a 1/3 divider would set the pci bus to 44mhz which may be to much for one or more of your cards.
The Agp bus has it's own divider as well which keeps it running at, or around, 66mhz. The agp divider should be set to 2/3 for a 100mhz fsb or 1/2 for a 133mhz fsb.
Your problem could possibly be the vid card which would explain why the screen stays black when you boot with the fsb set to 133.
See if you can set the agp divider to 1/2.

my video card is a pci not agp

thanks for the info though i don't want anything to fry from me playing around with it since i can't afford to replace it right now lol. thanks alot for the help

Tappwin said:

my video card is a pci not agp

thanks for the info though i don't want anything to fry from me playing around with it since i can't afford to replace it right now lol. thanks alot for the help

Click to expand...

Your welcome,

It could still be the vid card though, if the board only supports a 1/3 pci divider them setting the fsm to 133 will set the pci bus to 44 which might be too much for it.

We'll figure it out yet for ya, just need to figure out the exact model board your usin' is all

http://www.chaintech.com.tw/PROD/7xMB/7AIA5E.htm

Is this your board?