Overclock your G4 bus speed up to 150MHz !
Overclock your G4 bus speed up to 150MHz !
Here is how to do ! Pour savoir comment faire, par ici
This modification is possible only on QuickSilver and DigitalAudio G4.
Here are data sheets used for this overclock.
IMIC5002 (IMIC5002.pdf)
IMIC5003 (IMIC5003.pdf)
The IMIC5002 is a frequency generator used to control the PCI frequency. The IMIC5003 is used to control the bus frequency.
In the second data sheet, there is the famous frequency table of the IMIC5003.
To overclock the bus, we'll change the default settings of the IMIC5003 generator to get 150Mhz instead 133MHz.
Here is how to do. Noted than you'll need soldering tool and a 22ohms resistor.
First, locate the IMIC5003 on motherboard in the corner formed by dautherboard and memory stiks.
To generate the default bus frequency (133MHz), SEL0 and SEL1 were internally pull-up and SEL2 was connected to the ground (GND) trought a 1Kohms resistor. Personnally, I never found this resitor.
So, to make to right sequence, we set SEL1 to « 0 » with a jumper.
And we set SEL2 to « 1 » with a 22ohms connceted on a close 3.3V free tab (left tab on a unpresent capacitor C187).
That's it !
If you have any questions or commentary (regarding my bad translation by exemple... ), send it ! jonathanrenaud@yahoo.fr
Note :
Don't forget than CPU and memory frequency will be increased proportionally.
On my DigitalAudio G4, the memory sticks (3 x 512MB Micron MT16LSDT6464AG-133B2) don't overheat and are perfectly stable.
Also, noted than OSX won't recognize the new bus and CPU frequency. Anyway, it's working !
Some link to boost your old G4 !