PowerBook G3 VCore Adjustment (?)

Astal

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Jul 16, 2022
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Hello! I have my G3 wallstreet and I'm trying to figure out where to adjust the vCore! I heard it might be on the CPU card, I can't find any documentation beyond "I'm adjusting the vCore" on what the hell it actually is and any insight would be welcome.
 

JDW

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I too have a Wallstreet but never tried to overclock it, so I cannot provide help about voltage adjustments. But you only need to adjust voltages when overclocking, and how are you going about that?
 

Astal

New Tinkerer
Jul 16, 2022
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I too have a Wallstreet but never tried to overclock it, so I cannot provide help about voltage adjustments. But you only need to adjust voltages when overclocking, and how are you going about that?
I've been in contact with DosDude and Bolle, they helped figure it out, there's a resistor divider, I installed an IBM PPC750S on the card is why, and it wants a much lower vCore than the Motorola XPC750.
 

Astal

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Jul 16, 2022
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We figured it out.

R49 and R48 are in parallel and then R47 is in series with it. This makes up R2 on the formula for the vCore...

vCore = 1.23 * (1 + 10k/R2)

1668193010182.png


These here
 
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JDW

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So basically you swapped the CPU on your card in the PowerBook Wallstreet, not because the CPU was bad, but because you were hoping for better performance, even at the same clock speed, but you found that you needed to adjust the voltage going to the new CPU in order for it to become stable, correct?
 
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Astal

New Tinkerer
Jul 16, 2022
57
21
8
An Alternate Timeline
So basically you swapped the CPU on your card in the PowerBook Wallstreet, not because the CPU was bad, but because you were hoping for better performance, even at the same clock speed, but you found that you needed to adjust the voltage going to the new CPU in order for it to become stable, correct?
I had a CPU sitting here and it was the first thing I saw to glue it on to :p

And I am wondering why Wallstreet and not Pismo or Lombard? :)
Because I own a Wallstreet already
 
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