Overclocking an iMac

Discussion in 'PowerPC Macs' started by reddrag0n, May 16, 2019.

  1. reddrag0n macrumors 6502

    reddrag0n

    Joined:
    Oct 1, 2007
    Location:
    Canada
    #1
    Now before you all say look online, i have. All i have seen is how to OC the 100mhz FSB iMacs and the 167mhz FSB ones, but there is one that is not online. The 17" 1GHz 133mhz FSB from 2003 (PowerMac6,1 M8935LL/A).

    I was wondering if there was a way to push the FSB and push the cpu to 1.25GHz

    Screen Shot 2019-05-16 at 10.26.09 PM.png Screen Shot 2019-05-16 at 10.26.15 PM.png
     
  2. Raging Dufus macrumors regular

    Raging Dufus

    Joined:
    Aug 2, 2018
    Location:
    Kansas USA
    #2
    I'll admit upfront that I'm out of my depth when it comes to overclocking. I'm familiar with the process but haven't yet attempted it, so take what I'm saying here FWIW.

    If you can't find what you're looking for to overclock the system bus, then why not just overclock the CPU? The end result would be the same, at least as far as your CPU speed goes. Plus, your machine wouldn't require new RAM.

    Later versions of the iMac G4, including the 1.25 GHz, use the same chip as your 1.0 GHz, a PPC 7445. There's info out there to overclock the 7445, here's an example.
     
  3. timidpimpin macrumors 6502

    Joined:
    Nov 10, 2018
    Location:
    Cascadia
    #3
    I wouldn't overclock any iMac, because they all have sub-par cooling as it is. And any performance increase will be very tiny. Plus... overclocking will shorten the life of an already old CPU.
     
  4. reddrag0n thread starter macrumors 6502

    reddrag0n

    Joined:
    Oct 1, 2007
    Location:
    Canada
    #4
    The link you posted is for the 167fsb iMacs, mine is the 133fsb version. Sure, i could blindly try to overclock mine to what that site says, but without some information backing up what i am looking for, i'm not willing to risk destroying my machine.

    Plus his link (even though it's dead) links to the 7455 processor, even though he talks about the 7445.
    You see where i am going with this...
     
  5. reddrag0n thread starter macrumors 6502

    reddrag0n

    Joined:
    Oct 1, 2007
    Location:
    Canada
    #5
    I found the document, hunted wayback machine and landed on freescales site with the document. I was wrong about the document not showing the 7445 cpu, since it's in the doc. But from what i am seeing, that cpu is only capable of a FSB of 133mhz. And it's not showing anything about being able to go past the 1GHz barrier.

    I tore apart my iMac, and i was able to find the jumpers, but they are set up the exact way as illustrated in the pic on the 167FSB version showing 1.25GHz.
    [​IMG]

    Which means that if i were to OC the FSB, then it would be stock at 1.25GHz. Now to just figure out where those specific jumpers reside.

    As for the ram, i am already using ddr-400/PC-3200 1GB sticks
     
  6. Raging Dufus macrumors regular

    Raging Dufus

    Joined:
    Aug 2, 2018
    Location:
    Kansas USA
    #6
    Aaaaaannd that's why I haven't tried overclocking yet. Too much conflicting info, too little certainty, too much risk.

    I'll still give it a try someday though, just because I like to tinker. So I totally get what you're trying to do there, @reddrag0n. Good luck with all that, and if you find a reliable source of info please share.
     
  7. reddrag0n thread starter macrumors 6502

    reddrag0n

    Joined:
    Oct 1, 2007
    Location:
    Canada
    #7
    I’m wondering, what was that old site that had almost every possible mac that could be overclocked? I think it ended with *.jp or something to that effect. I remember way back when i was overclocking Sawtooth cpu’s for Digital Audios and vice versa, it had some really good info for doing all of that. I think they had info on the iMacs too.
     
  8. Woodcrest64 macrumors 65816

    Woodcrest64

    Joined:
    Aug 14, 2006
    #8
    Wow, I did not think you could ever overclock an iMac.
     
  9. LightBulbFun macrumors 68000

    LightBulbFun

    Joined:
    Nov 17, 2013
    Location:
    London UK
    #9
    https://forums.macrumors.com/threads/worlds-fastest-imac-g4-2-ghz-imac-g4-cpu-upgrade.2125765/

    this thread may be of use to you :)
     

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8 May 16, 2019