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iBook 2001 Overclocking Guide
100Mhz bus speed, 600MHz CPU Speed
By Tycho
Published: 8/21/2000

Disclaimer/Caution: This article is for entertainment purposes only. The author nor the site publisher assumes any liability for modifications you make to your iBook, which voids the warranty and overclocking may affect short or long term reliability. Incorrectly done modifications may cause immediate system damage.
Intro | Removing Screws | Resistor Mods | Benchmark/Game Tests

Step3: Resistor reconfiguration and PLL tables
I used several Japanese sites for reference in determining the PLL configs for the various multiplier settings. Some of the information was confusing to me, so I will post both the information they listed, and the information organized in a way my brain could more easily process it.

speed table1

PLL table

I do not fully understand the why behind these settings, all I know is that the ones I tried seemed to work fine (I kinda figured it out a little, but I would still like more insight into these settings). One interesting thing to note is that the PLL config for this chip is identical to that of a PPC 750L and PPC 7400/7410.

The first thing I did was reconfigure the bus speed [raised bus to 100 MHz (PCIx3) from 66 MHz (PCIx2)]. To do this, I moved the resistor (471 KOhm I believe) in position R341 to position R340. The images below show the location of these resistors and the bottom PLL bank as well as close ups of the before and after resistor positions (ugh, it looks as if I soldered it with my feet, but I checked it with my multimeter and I was getting the proper resistance across the 2 pads, so I decided it was good enough).

R341/R340 locations


Next up was the R269-R272 resistor table (shown in motherboard picture above). I knew I wanted at least 600 MHz, and the settings for 600 and 650 (which I was hoping for) are the same, so off came R271.


motherboard top

These were reconfigured to the 600-350 MHz setting as shown in the PLL tables. I then reinstalled the motherboard and it was at this point that I realized that banks can be reconfigured even if the whole motherboard is left in the ibook by simply bending the cast plate that cools the CPU up and back (the copper wire bends very easily, so be careful not to bend it too far and stress it as this would lead to less efficient cooling).

mb installed

I later installed a pair of wires attached to the pads of R43 so that I could shut down and boot up at 650-350 (for stability testing...the 650 setting proved to be unstable in the long run).

wire mod

With the bus at 100MHz and the CPU at was time to re assemble and enjoy the fruits of my labor.

Step4: reassembly
I will note some things that I forgot when reassembling my iBook. First of all, DON'T FORGET TO PUT THE AIR PORT RISER BACK IN. I got done reassembling it and went to put my air port card in when...DOH! slot for it to go apart the iBook came...again. Also, I think it would be wise to use different colored nail polish over the heads and holes of the screws (use blue for the screws and screw holes on the bottom and red for the screws and screw holes on the top...or any color of your choice). This would prevent the dreaded extra parts dilemma (I still have 1 screw that I can't find a home for).

Other than is pretty straightforward, just reverse disassemble it :P

Next Step: Benchmark/Performance Tests

Index of iBook Overclocking Guide

Intro | Removing Screws | Resistor Mods | Benchmarks/Game Tests

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