For wtp

[Dputiger]

Wtp, you seem to know a lot about this stuff so I'm going to impose on your good graces and ask again. http://sysopt.earthweb.com/forum/smile.gif

My mobo seems to lock its PCI bus speeds: That is, they alternate between 30 and 33 no matter what the FSB is set for (60, 66, 75, and 83).

Now, I can barely stabilize my machine at a 75 Mhz FSB if I keep the PCI cards as cold as possible (below 26' Celsius).

Could my PCI cards be running too slowly to keep up with a 75 Mhz FSB? At that setting my PCI's are only doing 30 Mhz--could that be what's screwing them up, and would going to 83 Mhz (and a 33 Mhz FSB) make the difference?

[wtp]

are you having just lockups. around 30MHz is NORMAL for the PCI bus. Yes, depending on your CPU and cooling, up to 100MHz is A-OK. Some CPUs just suck and give up on you. I don't know about that locked PCI bus, but they are most of the time divided. I think the frequently used frequency divider for a PCI BUs is 1/3 the FSB speed. Whatever the FSB is on your computer, if you divider is 1/3, it'll take 1/3 of your FSB, and that will be your PCI Bus Speed. The higher your FSB, the faster your PCI Bus. Of course.... 100MHz and lower will NOT affect your PCI most likely.

[This message has been edited by wtp (edited 06-03-2000).]

[This message has been edited by wtp (edited 06-03-2000).]

[otheos]

I don't know if I understand well, but if your system locks at FSB 75 unless your PCI cards are cooled it is the PCI cards that can't stand the high FSB. The divider is 1/3 at 100FSB but only 1/2 @ 66,75,83 so @ 75 the PCI bus runs @ 37.5 and @ 83 at 42Mhz.
When you set it to 100 the dividers go to 1/3 and you start all over untill 133 where the dividers go to 1/4. So overclocking with 75/83 bus is putting pressure to your PCI bus.

[Dputiger]

This is how my motherboard manual lists the information:

JP10, JP11 Host/PCI bus Frequency
(1-3,2-4) (1-3,2-4) 60/30
(3-5,4-6) (1-3,2-4) 66/33
(1-3,2-4) (3-5,4-6) 75/30
(3-5,4-6) (3-5,4-6) 83/33

I'm assuming this means that the PCI bus is either 30 or 33, depending on what the Host Frequency is (I'm also assuming Host Frequency=Front Side Bus).

Thoughts?

Note: This motherboard was designed to accept a Cyrix MII chip which USED an 83 Mhz bus to transfer data.


[This message has been edited by Dputiger (edited 06-03-2000).]

[wtp]

that's probably it. i don't know about locked ones, so hope someone helps you out! http://sysopt.earthweb.com/forum/smile.gif

wtp http://sysopt.earthweb.com/forum/smile.gif

[akaBruno]

I'm not so certain that it is a bus speed problem. It could very well be lacking the needed core voltage to stablize. Those **** proprietary boards of IBM jump right from 2.2 or 2.3 straight to 2.8 and that's pretty hot, just to test it.
It may be time to stop beating that poor old horse and get a new one. A new mobo and cpu at least.

[wtp]

yeah, i hate **** brand name computers. I prefer generic, custom made, one of a kind.

[Dputiger]

Yeah--I'm working like crazy hoping to make enough money to build a new one at the end of the summer. Unfortunately I go to a college that charges slightly less than the GDP of Taiwan to attend for a year so money's really tight.

THe FSB problem is important to me because I just bought an AMD K6-2 400 to use for its 2x/6x multiplier. (akaBruno knows about this).

So, I was hoping to kick the FSB up to 75 or even 83 Mhz and see what happened. I've heard that chips will tolerate a voltage jump from 2.2 to 2.8 IF they are cooled enough--what temperature is 'enough'? 32' Celsius, give or take? Or is this just too dangerous? (This chip is an AFQ)

[akaBruno]

Dputiger:

You were given a lot of great advice on how to run that 400 chip at 6x66 @ 2.2v. You haven't even tried that yet, so why all the B.S.ing around w/ this 266.

Don't worry about what you don't have. Just make do w/ what ya got.

People here are genuinely trying to help. But you're not helping yourself w/ all this.
Keep it down to one post at a time. And tackle one problem at a time.

No offense intended,

Bruno

[wtp]

any K6-2 should be kept under 50C, over this, and instability occurs. Mine is rock solid with full CPU load at 49, and never goes over. close.. http://sysopt.earthweb.com/forum/smile.gif


wtp http://sysopt.earthweb.com/forum/smile.gif

[Dputiger]

Ahhh...I may have been unclear:

I haven't gotten my K6-2 400 yet, so I can't play with it. (it's in the mail). http://sysopt.earthweb.com/forum/smile.gif I posted some stuff about my K6-266 earlier because that's what I was working with up till yesterday--I'm done with it now.

Sorry if I seem a bit redundant--I'm just concerned about playing with voltage because I've heard repeatedly that that's the fastest way to blow a CPU and mobo, not just the chip.

No offense taken, Bruno--I've gotten ahead of myself and posted too quickly and too much a couple of times. I've said it before and I'll say it again--ya'll have been awesome at giving help and I really do appreciate it. I've learned a ton since signing on here.