Early 2008 Mac Pro Dead Memory Riser

Discussion in 'Mac Pro' started by iriejedi, Mar 13, 2016.

  1. iriejedi macrumors 6502a

    iriejedi

    Joined:
    Oct 4, 2000
    Location:
    Nor Cal
    #1
    Just curious - how common is this problem... granted in 8 years first real issue.....

    Everything points to the single Rev A riser.

    (Side question anyone know the difference between Rev A and Rev B version of the card?)

    Got 12gb on the other riser so can barely notice... but still.... if that one goes...

    ordered a spare. But curious has anyone else dealt with this?

    Cheers
    IJ.
     
  2. Machines macrumors 6502

    Machines

    Joined:
    Jan 23, 2015
    Location:
    Fox River Valley , Illinois
    #2
    DDR2 FB-DIMM modules often overheat and fail . That would over a period of time place thermal stress on the memory risers , causing them to fail as well .

    There are two types of pre-Nehalem memory risers . One type for the MP 1,1 (2006) and 2,1 (2007) . Another type for the Mac Pro 3,1 (2008) . They are not interchangeable .
     
  3. iriejedi thread starter macrumors 6502a

    iriejedi

    Joined:
    Oct 4, 2000
    Location:
    Nor Cal
    #3
    Thank you. Ordered a spare MP 3,1 riser - it would make sense being the one closest to the video card from a heat perspective (especially with the 5870 installed...... did lose some DIMMs man years ago - but fortunately were replaced with 'lifetime warranty' - no questions asked... New Egg I believe. Regardless - makes me wonder if those were top of bottom DIMMs....hmmmm

    only 2 X 1 gigs on the failed riser... will keep the big bank (12 gigs) on the bottom.... just in case...

    Have a great day!
     
  4. Machines, Mar 13, 2016
    Last edited: Mar 13, 2016

    Machines macrumors 6502

    Machines

    Joined:
    Jan 23, 2015
    Location:
    Fox River Valley , Illinois
    #4
    You can get an entire 667 MHz 32GB kit (8 x 4GB) for around 30-40 bucks on eBay .

    http://www.ebay.com/itm/32GB-8x4GB-...038711?hash=item2eeca9adf7:g:~GQAAOSwAuNW4a9X

    Hynix model HYMP151F72CP4N3-Y5 .

    The only thing you have to worry about is the Mac will not detect the thermal sensors of the memory modules , so you might have to manually adjust the case fan rotations with Macs Fan Control .

    You do not need those fancy fat heat spreaders qualified by Apple . Flat spreaders are fine .

    hynix4GB.jpg
     
  5. iriejedi thread starter macrumors 6502a

    iriejedi

    Joined:
    Oct 4, 2000
    Location:
    Nor Cal
    #5
    Sweet deal. But I'm 99.9% sure it is the board itself - not the RAM. Moved stuff around up and down in the slots - the RAM on the bad riser board never shoes up. But is fine once I move it back to the good riser board.

    Also in the system profiler, the memory will shift to the left or right side of the graphics display as I swap the boards up and down. So at least the connection to the mother board is still good.

    Fingers crossed. Sadly, I can totally afford a new Mac Pro... but this 2008 still does the job - Start Craft II still play maxed out settings and my XBOX One covers the rest of my graphics needs :) .

    Impressed with the design effort, but not for the price and lack of 'inside space'. Found a solid supply of Referb 2012s out there... that is the back up plan for any terminal failures unless Apple pulls some magic out of their hat on a nMP upgrade.

    Cheers.
     
  6. Machines macrumors 6502

    Machines

    Joined:
    Jan 23, 2015
    Location:
    Fox River Valley , Illinois
    #6
    You mean a Cylinder Mac Pro 6,1 ? It is basically a FCPX and Logic optimized workstation . Third party apps run nicely on the cMP (Mac Pro 1,1 - 5,1) models .

    There is no functional difference between an upgraded Mac Pro 4,1 > 5,1 (2009 factory) and a genuine Mac Pro 5,1 (2010-12 factory) model , if somebody refurbished it properly .

    There is no telling what will replace the current Mac Pro . I am personally hoping for a Dual E5 Broadwell Mid Tower workstation , which should be possibly in April . I don't need any more iToys in my life ...
     
  7. Morriss macrumors member

    Joined:
    Jul 24, 2008
    #7
    I just replaced a bad bottom riser a few weeks ago. Mac was slow to boot from a cold start. Hairdryer applied to the riser "fixed" the problem. I thought it was a bad MB, so was happy to only have to replace the riser. Been running fine with the new riser.
     
  8. robert05au macrumors regular

    robert05au

    Joined:
    May 19, 2005
    Location:
    Dubbo, NSW
    #8
    another thing that can cause issues with the risers and ram is good old dust. I thought I had a similar issues cleaned all with a good vaccum clean did the trick for me all works as normal
     
  9. iriejedi thread starter macrumors 6502a

    iriejedi

    Joined:
    Oct 4, 2000
    Location:
    Nor Cal
    #9
    Follow Up on the issues. Thank you all for the replies.

    Riser was bad... and so were DIMMs... (original stock 2x2gb set) a friend recommended a fan control utility to increase air flow... at this time noted the bottom front fan only twitched, like a nervous tick... considering this likely root cause of the failure.

    Get that fixed hopefully this weekend... still hope to get a couple more years of of this old girl. For all I know that fan has been dead for years...
     
  10. Machines macrumors 6502

    Machines

    Joined:
    Jan 23, 2015
    Location:
    Fox River Valley , Illinois
    #10
    It all makes sense, now . Dead fan that is supposed to cool memory modules that get too hot anyways normally ! :eek:
     
  11. owbp macrumors 6502a

    owbp

    Joined:
    Jan 28, 2016
    Location:
    Belgrade, Serbia
    #11
    Sorry for the intrusion, just two quick questions if i may. :)
    How much of the temp rise is average with flat heat sink modules and does the sensors on riser itself still work?
    I'm not so much concerned about temperature itself as much as i would like to avoid making it loud with high fan speeds.
     
  12. Silencio macrumors 68020

    Silencio

    Joined:
    Jul 18, 2002
    Location:
    NYC
    #12
    I remember one of the risers on my 2008 Mac Pro went "bad" after I moved cross country. Even tried borrowing a riser from another machine at work, and it still didn't show up when I installed it in my machine.

    I very carefully cleaned out the affected riser slot on my logic board, and that brought it back to life.
     
  13. Machines macrumors 6502

    Machines

    Joined:
    Jan 23, 2015
    Location:
    Fox River Valley , Illinois
    #13
    I don't have access to a Mac with that memory kit installed at the moment , so I can't say what its temps are .

    The risers will still have working thermal sensors .

    You can access them with a program by Bresink called Hardware Monitor .

    I don't think you need to worry about the Mac raising it's case fans to a high and loud speed , when adding these memory modules .

    What I would worry about is manually adjusting the case fans in your Mac , so that everything stays cool . The Mac won't do that in this situation . You need a copy of Macs Fan Control
    --- Post Merged, Mar 17, 2016 ---
    Dust clogged the memory riser interface slot on the logic board . It is very important to keep dust out of the Mac Pro . Grab a front case filter or clean the inside of the Mac twice a year with a compressor . 60 PSI at 6 inches away .
     

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