Mac Pro Memory/Riser problems ; Comments please?

Discussion in 'Mac Pro' started by petrified, Jul 19, 2008.

  1. petrified macrumors newbie

    Mar 30, 2008
    Hey guys!

    I woke up this morning and booted my (08)mac pro only to find 4GB of ram being booted up on riser B, and my riser A didn't register the other 6GB.

    I started to troubleshoot the problem by testing to see if it was my RAM that had a problem, or the riser card itself.

    Config; Riser A - DIMM 1 (2GB), DIMM 2 (2GB), DIMM 3 (1GB), DIMM 4 (1GB)
    Riser B - DIMM 1 (2GB), DIMM 2 (2GB), other 2 DIMMs empty

    Troubleshooting all on Riser A

    I started by switching out the two 1GBs, booted, system showed that my Riser A DIMMs 1 & 2, registered, but only 1GB each instead of 2GB.

    I then proceeded to switch the 2 1GBs into riser A DIMM 1 & 2, and the 2GBs in riser A 3 & 4. Didn't register any of the mem modules.

    I then took 2 x 2GBs from the riser B and replaced it with Riser A's 2GB modules, then i switched the riser Cards themselves. viola! 10GB showed up.

    Throughout the whole process, i noticed that when the memory modules don't read, there is always a RED LED on the mem module itself that lights up. So now i'm wondering what is the problem that is plaguing my memory cards? I might add additional ram some time soon and i don't want these problems to happen again.

    It's strange at times too, whenever i get a Kernel panic, and i reboot, instead of 10GB, only 8GBs show up, and when i reboot again, 10GBs show up.

    This memory problem is starting to concern me.

    The only conclusion that i am able to draw is, perhaps one of my Riser cards is spoilt, and should i send it for repair? I am using 3rd party RAM, if i send it with my riser cards, it will void my warranty with apple, yea?

    Thanks for your help in advance!!

  2. Spikeanator6982 macrumors 6502

    Jun 13, 2007
    you could run the hardware test from the system disk.

    Just have to trouble shoot till you figure out what the problem is. Sounds like one of your 2GB dimms or both may be bad to me, but Idk for sure of course.
  3. Pixellated macrumors 65816

    Apr 1, 2008
    In a Mac Pro you can change the GFX, the RAM, and the HDDs without voiding your warranty.

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