Power Mac G5 (june 2004) processor upgrade compatibility

Discussion in 'PowerPC Macs' started by GuiPol, Apr 22, 2018.

  1. GuiPol macrumors member


    Mar 1, 2018
    Hello guys !
    So i've got my hands on 2 power mac G5 recently, apparently dead :
    The first one would be this one : https://everymac.com/systems/apple/powermac_g5/specs/powermac_g5_2.0_dp.html
    Dual 2 ghz from june 2003 stamped powermac 7,2
    and the second one :
    https://everymac.com/systems/apple/powermac_g5/specs/powermac_g5_2.0_dp_2.html which comes by the model number powermac 7,3.
    also Dual 2 ghz but from june 2004. Only difference is the "FX" at the end of the processor name : powerpc 970 FX for this one.
    They both have some trouble (not booting or freezing randomly) and i've found are VERY picky about a lot of things !

    Anyway, to the point : i've come to believe that for the second one, the powermac 7,3, one of the two processor is rightfully in the blue (hence the freezing troubles.. already ordered new ram to be sure it's not that)... so i was wondering : Is it possible to put 2 x 2.3 Ghz (air cooled) inside this machine instead of the 2 x 2 GHZ.
    Found some on ebay but they are from the A1177 model. Will that be compatible with the screw scheme of the A1047 that i have ? My dual proc is with torx screws by the way (the one you're suppose not to put out the board)

    I've read some has done it without a problem... but ..you know... i prefer to be sure.

    Thanks guys. I may have a few others questions regarding sata upgrade and wifi compatible card (guess broadcom chip will do like the G4) but i'll start another thread for that in due time.
  2. AphoticD macrumors 68000


    Feb 17, 2017
    The A1117 (Late ‘05 / 11,2) Dual Core 970MP CPU cards are quite different to the A1047 970 and 970fx CPUs found in the earlier models. Anything is possible of course, but I don’t think they would be easily modified. The A1117 cards take additional power input directly from the PSU, whereas the A1047 is powered via the logic board connector.

    The safest bet would be the 2x 2.0ghz or possibly the air cooled 2x 2.3ghz 970fx from the 7,3 series.

    Before spending any money, I would try running Apple Service Diagnostics (ASD) v2.5.8 and go through the hardware tests as well as the CPU calibration if needed.

    Search on these forums for a link to the ISO on dreamsupport and username / password combo to download.

    Burn to CD and boot into the OF hardware test by holding the option key on startup.

    If the CPU(s) fail with temperature out of range (overheating) faults, the fix is typically to just dismantle and replace the thermal paste. I would use a quality compound like Grizzly Kryonaut (12.5w/MK). In my experience, even a 6.5w/MK silver paste wasn’t sufficient to stabilize temps in a Dual 2.0ghz 970, however the 970fx was slightly more efficient and should run cooler than the original 970.
  3. GuiPol, Apr 22, 2018
    Last edited: Apr 22, 2018

    GuiPol thread starter macrumors member


    Mar 1, 2018
    thank you for your answer.
    Yes i think that would be my best bet but i can't seem to find one yet unfortunately.
    I'll keep searching though maybe i'll find one (i mean 2) at a good price.
    I've already dismantle the cpus and put fresh thermal paste on them (some high quality one).
    But i couldn't test the stability since now it doesn't even boot up... It starts, fans kicks off momentarily, then bam everything shuts off.
    I'v read in the service manual than one has to reset PMU if he touches the mainboard. I didn't do that and the battery (onboard) has been depleted (reads 0v). So tomorrow i'll be searching for a new one and try to boot. If that boots i'll test the stability with the new and horribly expensive thermal paste i've put on it (the arctic mx4)..
    Thanks for your input AphoticD, i'll keep you posted for the results ;)

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