jozl.l
Level 1 (11 points)
Mac OS X

Q: 2008 Mac Pro not reading all of my RAM.

I have a 2008 Mac Pro with 12gb of ram. I have 4, 1GB Dimms and 4, 2GB Dimms for a total of 12 GB. Problem is my computer is only reading 10 GB. I have the 4, 2 GB Dimms on the top board and 4, 1 GB Dimms on the bottom board. Is there a better way to configure the ram?

Mac Pro, Mac OS X (10.7.5)

Posted on Aug 1, 2015 2:46 PM

by lllaass,Solvedanswer
lllaass lllaass
Level 10 (189,435 points)
Desktops
A:

Sounds like you have a bad stick or two of memory.

Open system profiler and click on he Memory in the left-hand side and you see the memory. It may not say OK for two sticks

OS X: About System Information and System Profiler - Apple Support

Posted on Aug 1, 2015 3:00 PM

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jozl.l

Q: 2008 Mac Pro not reading all of my RAM.

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  • by lllaass,Solvedanswer

    lllaass lllaass Aug 1, 2015 3:00 PM in response to jozl.l
    Level 10 (189,435 points)
    Desktops
    Aug 1, 2015 3:00 PM in response to jozl.l

    Sounds like you have a bad stick or two of memory.

    Open system profiler and click on he Memory in the left-hand side and you see the memory. It may not say OK for two sticks

    OS X: About System Information and System Profiler - Apple Support

  • by jozl.l,

    jozl.l jozl.l Aug 1, 2015 4:32 PM in response to lllaass
    Level 1 (11 points)
    Mac OS X
    Aug 1, 2015 4:32 PM in response to lllaass

    Thanks Illass. Looks like you're right. All of my slots are occupied but the profiler indicates two empty slots. I assumed that meant they are not being read by the processor because they aren't installed properly but it may well be that they're not being read because one or two sticks are damaged.

  • by Grant Bennet-Alder,Helpful

    Grant Bennet-Alder Grant Bennet-Alder Aug 1, 2015 7:24 PM in response to jozl.l
    Level 9 (61,083 points)
    Desktops
    Aug 1, 2015 7:24 PM in response to jozl.l

    Te Mac Pro with Xeon Processor features built-in Memory Error detection and correction Hardware found only the Xeon Processors. This Hardware is used aggressively during the Power-On Self Test to determine whether ANY memory errors (correctable or not) occur during the few seconds the memory test is running. If any occur, those slots are declared "empty" and the system will not use them. You should plan on replacing those modules soon.

     

    However, if the Mac Pro is run another time from power off, through the Power-On Self Test, it is possible that some times those modules might pass, and be used by the system. This does not make them good. It just means the Power-On Self Test did not catch them that time.