b.boyd3691
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Q: mac pro 1,1 not detecting all ram after kernel panic

hello,

my mac pro 1,1,2x 3.0Ghz, quad core, 24gb ram os x 1.7.5, just had a kernel panic and shut down, after being on for 12 plus hours, mostly sitting idle. when i restarted the mac pro, now it is only recognizing 12gb of ram on one riser and the other riser shows to be empty, the dimms are installed as riser a = 4gb4gb2gb 2gb, riser b = 4gb4gb2gb2gb, all are matched pairs. all ram has been installed and working for 7-8 months without any problems. this is the first time my mac has ever shut down from a kernel panic by itself, and it's never failed to see half the ram before, in fact it has been running great for quite awhile until now. i'm not sure what's going on and i hope someone can help me get this figured out and find a solution to this problem, thanks in advance.

 

bill

Mac Pro, Mac OS X (10.7.5), 1.1 ssd,24 gb ram, 2x3.0Ghz d.core

Posted on Dec 29, 2015 5:34 PM

by Grant Bennet-Alder,Solvedanswer
Grant Bennet-Alder Grant Bennet-Alder
Level 9 (61,385 points)
Desktops
A:

If you remove the side door with the power on, the red lights indicate the failed DIMMs.

Posted on Dec 29, 2015 6:23 PM

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b.boyd3691

Q: mac pro 1,1 not detecting all ram after kernel panic

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  • by Grant Bennet-Alder,Helpful

    Grant Bennet-Alder Grant Bennet-Alder Dec 29, 2015 7:26 PM in response to b.boyd3691
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    Dec 29, 2015 7:26 PM in response to b.boyd3691

    You have a RAM failure.

     

    The Mac Pro features Error Correcting Code RAM with a hardware assist built into its Xeon processor. The Mac Pro 1,1 uses FBDIMMs that get hot and do not have a long lifetime. Working for 7-8 months does not guarantee working tomorrow.

     

    The Error correction is used aggressively at Startup, and any DIMMs found to have any errors during the brief execution of the Power-On Self Test have their slots declared "empty". This is not an anomaly, those DIMMs were found to be BAD.

     

    If those DIMMs have Vendor stickers on them, you may be able to get them replaced under the Vendor's warranty.

     

    The kernel panic you just encountered could be part of the same problem. You can find the report and examine it and post it if you like.

     

    Mac OS X: How to log a kernel panic - Apple Support


    RAM problems show themselves as kernel panic, machine check, often detected by multiple processors at once.

  • by b.boyd3691,

    b.boyd3691 b.boyd3691 Dec 29, 2015 6:18 PM in response to Grant Bennet-Alder
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    Dec 29, 2015 6:18 PM in response to Grant Bennet-Alder

    Grant Bennet-Alder,

     

    thank you for your info, i was wondering if ram failure was the issue. that said does this mean that all the dimms on the riser showing it's empty are bad ? also on the about this mac pro window showing the two risers the one that shows empty is on the left, is that the bottom or top one ? thanks

  • by Grant Bennet-Alder,Solvedanswer

    Grant Bennet-Alder Grant Bennet-Alder Dec 29, 2015 6:23 PM in response to b.boyd3691
    Level 9 (61,385 points)
    Desktops
    Dec 29, 2015 6:23 PM in response to b.boyd3691

    If you remove the side door with the power on, the red lights indicate the failed DIMMs.

  • by b.boyd3691,

    b.boyd3691 b.boyd3691 Dec 29, 2015 7:01 PM in response to Grant Bennet-Alder
    Level 1 (0 points)
    Dec 29, 2015 7:01 PM in response to Grant Bennet-Alder

    Grant Bennet-Alder,

     

    i started it back up with the side off located the lights you mentioned, however i guess it has cooled down enough that it now sees all the dimms. so i guess i have to try and catch it if it shuts down again. i do have istat installed and the memory temps are as follows : mem module A1-140*, A2- 146*, A3- 128*, A4- 137*, B1- 167*, B2- 175*, B3-149*, B4-144*, from this would you say that B1 & B2 are most likely the bad ones?

  • by Grant Bennet-Alder,

    Grant Bennet-Alder Grant Bennet-Alder Dec 29, 2015 7:25 PM in response to b.boyd3691
    Level 9 (61,385 points)
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    Dec 29, 2015 7:25 PM in response to b.boyd3691

    Look at

    About This Mac > ... > Report > Memory ...

     

     

    eccerrors2.jpg

     

    graphic from Anandtech.com

     

    this report is STATIC, but can be invoked again for fresh data. Any with ECC Errors (as shown) are bad.

  • by b.boyd3691,

    b.boyd3691 b.boyd3691 Dec 29, 2015 7:26 PM in response to b.boyd3691
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    Dec 29, 2015 7:26 PM in response to b.boyd3691

    Grant Bennet-Alder,

     

    well it stopped seeing the A-riser, and the red light for dimm A-1 stays lit. so, my question is does that mean it's just one module bad? and because one dimm is bad the whole riser gets shut down? also this module is not one that ran a high temp, whats the normal temp for 4gb dimms? any info you have is greatly appreciated.

  • by Grant Bennet-Alder,

    Grant Bennet-Alder Grant Bennet-Alder Dec 30, 2015 1:47 PM in response to b.boyd3691
    Level 9 (61,385 points)
    Desktops
    Dec 30, 2015 1:47 PM in response to b.boyd3691

    When you fully populate every slot on Mac Pro 2006, 2007, and 2008, it RAM uses an obscure feature that allows it to do double-wide accesses. It may be that certain failures in the first DIMM could cause the whole riser-full to disappear because the processor has committed to double-wide accesses.

     

    Try pulling the first two out and see what it says about the rest.

     

    High temperature in one module does not predict imminent failure in that module. All these modules run hotter than RAMs used to run, and the general trend is that they fail more often than older  modules.