G3 iMac reports wrong clock speed

Discussion in 'PowerPC Macs' started by apple_iBoy, Jul 3, 2006.

  1. macrumors 6502a

    Joined:
    Oct 28, 2003
    Location:
    Philadelphia, PA
    #1
    I picked up an old iMac (summer 2001) model G3 earlier today. It was running Jaguar on the original 20GB hard disk.

    I swapped in a larger HD, which had a installation of Panther already on it. Booted up and everything seems A-OK, except that the CPU is being reported as 400 MHz in the System Profiler. I'm positive that it (accurately) said 500 MHz when the old Jaguar drive was in there.

    Anyone have any suggestions or thoughts?
     
  2. macrumors member

    Joined:
    Mar 25, 2004
    Location:
    Melbourne Australia
    #2
    You can check what the speed the machine left the factory as by checking the serial number here -> http://www.chipmunk.nl/klantenservice/applemodel.html

    The reported CPU speed on an Open Firmware based Mac can be changed using Open Firmware commands. These changes can be stored in NVRAM, so they will survive a reboot. However these changes will be cleared if you reset the PRAM, reset Open Firmware or perhaps even leave the machine off power for long enough.

    The machine might have been reporting 500 MHz due to an Open Firmware entry, but working with the hardware to install the new hard drive has removed this hack. Just a theory ...
     
  3. thread starter macrumors 6502a

    Joined:
    Oct 28, 2003
    Location:
    Philadelphia, PA
    #3
    fixed, maybe?

    Actually, it has now gone back to 500 MHz. I installed all the Panther updates to bring the system up to date, and after a reboot, the system is now properly reporting the speed.

    I'll keep an eye on it -- hopefully it stays there this time!
     
  4. macrumors 68040

    California

    Joined:
    Aug 21, 2004
    #4
    JFYI, I have Tiger on the same machine and a 120gb hd in it with 1gb of ram, too. Sweet little old iMac.
     

Share This Page