How do I overclock the bus on a Beige G3?

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How do I overclock the bus on a Beige G3?

Hi all,

I have a Beige G3 DT, with an XLR8 G4 400 MHz processor upgrade in it. I have the G4 running at 533 MHz, set with jumpers on the ZIF itself, but I have not done anything with the jumpers on the logic board. I want to overclock the bus speed to the 83 MHz limit, but so far I haven't found any clear instructions on how to do this. The instructions that I have found, all adjust the bus speed, the PCI speed and the processor speed. Is there any way to overclock the bus by itself? I have tried overclocking it according to the directions that I found, but it refuses to boot. Can someone please help me?

Daniel

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If you change the bus speed,

If you change the bus speed, all the other speeds that are multiples of it change too. You'll need to change the mobo CPU multiplier to keep it from going too high, unless your ZIF is one of the ones that ingnore the onboard multipliers in which case you'll have to change that. I've never used any ZIF upgrade in a Beige, but I'm goijg on what I remember reading when trying to troubleshoot the dead one of the G3/266 DT boxen of mine.

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I can't even get it to boot w

I can't even get it to boot with the stock 266 G3 in it.

Daniel

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Okay, I've tried using all of

Okay, I've tried using all of the settings for the 83 MHz bus with all of the clock speeds, both with the G3 in it and the G4 in it. It refuses to boot with either of them. However, the minute I take the jumpers out and put the stock jumper set back in, it boots with either processor in it. What is the deal??

Daniel

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ram speed?

Perhaps you are using PC66 ram that doesn't take kindly to running at 83mHz?

Also, some MLBs simply won't run at 83mHz, though I've yet to see one of those myself.

dan k

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The RAM seems to have been th

The RAM seems to have been the problem! Now, I'll have to play around with it and see which settings work with my G4 ZIF. Thank you so much!

Daniel

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Find the part labelled MPC106

Find the part labelled MPC106 and type in the rest of that line.

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Dr. Bob,

There's a Motorola chip in there labeled XPC106ARX66CG. Is that what you are looking for?

Daniel

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Yes that's exaclty what I wan

Yes that's exaclty what I wanted. That is the memory/PCI/60x bus controller. Yours is rated at 66MHz and thus you might have significant problems running at 83MHz. The Rev A and B G3's got 83 MHz parts, but the Rev C's got 66MHz to save money. However, on the bright side, you also got paddington instead of heathrow which brings faster IDE and better ethernet (though I can't remember is 100 megabit was enabled or not)

Oh, also since it begins with X and not M, the part is an engineering sample.

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Okay, so it would be best to

Okay, so it would be best to run at 66 MHz then? I was playing around with different speeds on the bus and the processor yesterday, and I noticed that I couldn't get speed that was totally stable, so is that the cause?

Daniel

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yes, I would not run the bus

yes, I would not run the bus above 66 mhz.

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Okay, thank you so much for a

Okay, thank you so much for all of your help, Dr. Bob.

Daniel

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