Old Mac Pro Memory issue

Discussion in 'Mac Pro' started by OldMacs4Me, May 4, 2018.

  1. OldMacs4Me macrumors newbie

    May 4, 2018
    I have spent the past week or so tracking down an issue where my Mac Pro 1,1 would reboot out of the blue. No rhyme nor reason to it.

    Finally decided that the issue was probably RAM. MemTest crashed about halfway through the first cycle. Tested just upper Riser with RAM removed from the bottom riser. MemTest ran clean. Moved lower board to top, put RAM back in, moved top board to bottom with RAM removed. Again MemTest ran clean.

    Finally restored original configuration and MemTest again crashed partway through the block test. Concluded that the lower riser slot on the mother board is bad, or there is a mother board problem that only effects the lower DIMM riser.

    Currently running on half RAM with the lower board empty. Quite stable in this configuration.

    Two questions: Would it be better to remove the lower board entirely? And can I fill the secondary pair of slots on the upper board, when the lower board is empty or removed?

    For legacy reasons I would like to keep this old guy running a few more years.
  2. vertical smile macrumors 68040

    vertical smile

    Sep 23, 2014
    I bet you already checked this, but on my Mac Pro 1,1, I had issues with one of the RAM boards. It turned out that it was just dust that got blown, blocking some of the contacts.

    Easy fix.

    I also had an issue with either the RAM itself not seating, and/or the one or both of the boards not seated correctly.

    I'm not sure which one it was, I ended up just removing everything, and reseating them.

    I hope that maybe one of these solutions might help you, so you don't ha e to worry about only using one board.
  3. OldMacs4Me thread starter macrumors newbie

    May 4, 2018
    Thanks for the thoughts.

    RAM on both risers has been re-seated.

    Actually took it outside and removed the DIMM risers so I could air onto the power supply as well. Will recheck the lower Riser slot but I am not hopeful, as the issue was already there when I did the cleaning.
  4. OldMacs4Me thread starter macrumors newbie

    May 4, 2018
    While the RAM solution greatly reduced the issue, it has not resolved it entirely.

    Looking back over old threads on several forums looks like it is about 90% likely to be the power supply.

    Good source for a reasonably priced replacement part?

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