OCing a NewerTech G4 card

[John_A]

Hi, I have a PowerMac G3 DT wich has a G4 upgrade running at 333Mhz installed. By changing jumper setting, I can get the cpu speed up to around 600Mhz.

Cpu utility software logs 22C or 71F temp at 333Mhz, wich I doubt is correct, with the stock G3 heatsink without fans.

Is the PPC 7400 (1st gen G4) sensitive to OCing? Do I need to get a larger heatsink, possibly with fans?

 

[Anonymous Freak]

What is the printed speed on the CPU? The 7400 wasn't officially available at 333 MHz, so it should run at higher than that no problem.

But it MAXED out at 550 MHz, and Apple even stopped selling that for a while, so I'd be careful overclocking.

 

[John_A]

The label on the box says g4/350 :O Wich means that I have underclocked it.. :I

Well, I guess that's the speed the cpu are tested for, don't want to remove the heatsink and the arctic silver paste right now..

Hmm, guess I have to increment the speed in small steps and run for a few days monitoring the temp..

 

[Byrd]

Hi, I have a PowerMac G3 DT wich has a G4 upgrade running at 333Mhz installed. By changing jumper setting, I can get the cpu speed up to around 600Mhz. Do I need to get a larger heatsink, possibly with fans?

Obviously you'll never get to 600Mhz, try for 400Mhz. G4s don't tend to overclock as well as G3s. Generally the CPUs run fairly cool but a quiet fan screwed on top with better thermal paste would be a must. My experience with overclocking G4s is that they either work 100% from the outset or die very quickly with Open Firmware dumps or kernel panics. It's not like PC x86 overclocking where it takes a lot of tweaking to get things running stably.

JB