Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[mcmcjohn]

Hello. The model I have is the Power Mac G4 Gigabit Ethernet. Originally, it had a single-core 1.33GHz CPU, but I wanted to upgrade to a dual CPU. So, I bought a DP 1.0GHz module from a Quicksilver, and I heard that by changing the resistor values, it could be overclocked to 1.2GHz or 1.33GHz. I moved the resistors accordingly to make it 1.33GHz. I also completed the additional 12V power supply modification.

However, after booting, both Mac OS 9 and Mac OS X still recognize it as 1.0GHz. Since this model only has a 100MHz bus, is it normal that changing the resistor like this doesn’t make it show up as 1.33GHz?

[robespierre]

All that the resistors can do is to change the multiplier which the CPU is told to use to configure its internal PLL (clock generator). The OS that is running doesn't "recognize" the CPU speed: software can either perform a CPU benchmark to measure processor performance, or else identify the model and revision of the processor to display the expected clock frequency. In most cases it's the latter, which means that overclocking will not change the displayed frequency.

A program like Newer Technology's Clockometer will try to measure the frequency by testing how many steps of the Decrementer register changes during a second (which comes from the real-time clock, not affected by the processor's clock). It should have a linear relationship to the real CPU speed, but there is some error. Since Apple doesn't want to receive complaints that their 1.0 GHz computer only reports "997 MHz", they don't use this type of measurement in System Profiler.

[aBc]

OR... you might even try:

https://macintoshgarden.org/apps/machspeed-control-combo

[laulandn]

Chances are you should believe what you see in "About this mac".  Apple does fudge the numbers (silly things like reporting a 666.66mhz as 667 so as to avoid being devilish), but you should see SOME difference, if changing the resistors did anything.

But DO give Clockometer (or something like that) a try, it doesn't lie.  If it is still reporting 1.0 ghz, then that is what your system is running at.  (Although the one I use is a MacOS 9 program, not sure if there is an X version).

This is strange, since what you did sounds like it should have worked.

[ssp3]

OR... you might even try:
https://macintoshgarden.org/apps/machspeed-control-combo

I always preferred this one:

[mcmcjohn]

Thank you, everyone. I tried running the Machspeed control on both OS 9 and OS X. On OS 9, it was recognized as 996MHz, but on OS X, it said the processor wasn’t supported and asked me to email the processor code to the company. I also checked with Clockometer, but it was likewise detected as an unsupported CPU, so I’m thinking of giving up for now… I guess I’ll just settle for 1GHz.