Mark Sebok
Level 1 (11 points)
Desktops

Q: Mac Pro 3.1 Memory Problem

Hello,

I have a Mac Pro 3.1. 16gb of ram in it, but sometimes only see 14gb.

 

8x 2gb 800 MHz DDR2 FB-DIMM

What could be the problem? Sometimes you see all memory and sometimes not.

screenshot.png

Mac Pro, OS X El Capitan (10.11)

Posted on Sep 9, 2016 4:47 AM

by lllaass,Solvedanswer
lllaass lllaass
Level 10 (188,131 points)
Desktops
A:

The 2006-2008 (1.1-3.1) use FBDIMM that run how and fail with time.

When they fail hopefully they disappear like you are experiencing. Frequently they fail when accessed and that can result in a kernel panic.

Sometimes reseating affected modules fixes the problem but frequently that fix is only temporary and the module has to be replaced.

Posted on Sep 9, 2016 6:26 AM

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Mark Sebok

Q: Mac Pro 3.1 Memory Problem

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  • by lllaass,Solvedanswer

    lllaass lllaass Sep 9, 2016 6:26 AM in response to Mark Sebok
    Level 10 (188,131 points)
    Desktops
    Sep 9, 2016 6:26 AM in response to Mark Sebok

    The 2006-2008 (1.1-3.1) use FBDIMM that run how and fail with time.

    When they fail hopefully they disappear like you are experiencing. Frequently they fail when accessed and that can result in a kernel panic.

    Sometimes reseating affected modules fixes the problem but frequently that fix is only temporary and the module has to be replaced.