Could use some advise on memory for Mac Pro 3,1 (2008)

Discussion in 'Mac Pro' started by omvs, Jun 7, 2014.

  1. omvs macrumors 6502

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    May 15, 2011
    #1
    An inlaw has a 2008 Mac Pro and has been debating a machine upgrade. However, to eek some more life out of the current machine, I suggested dropping in a SSD, new video card, and some more ram. I managed to prep a PC card using my 2009 MacPro4,1, which I thought was going to be the hard part -- I'm used to dealing with standard DDR3 dimms and had good luck with whatever I threw at my machine.

    So I found a 32g FBDIMM kit on amazon - it was only 667MHZ, but for $150 I figured the speed degradation was worth it. Unfortunately it caused all sorts of hassles - we couldn't get the system to recognize all 32G, and even with a reduced setthe system seems to run much, much hotter with the new memory - both the CPU temps and the DIMM temps look about 30-40deg F higher, and the system fans end up maxing out when photoshop is running. With the old memory, the temps stay much more reasonable and the fan doesn't kick into high gear.

    I had her try using just a few sticks of the new memory, and while it helps, running photoshop still kicks the CPU_MEM and EXHAUST fans >2000rpm.

    I did see info online mentioning that some FBDIMMs use smaller heat spreaders than Apple ones do, though these seemed the same size as the memory already in the machine. Also, I don't understand why the CPU temp is going up so much with the memory - at first we thought maybe the heatsinks on the CPUS were clogged with dust, but then switching back to the old memory fixed everything - seems like if it was just adequate heat spreaders only the DIMM's would be running hot.

    So we're going to return that ram, and look for something else. A crucial kit would seem to be the safe bet, but their prices for FBDIMM's are exorbitant IMAO. Can anyone recommend a 'affordable' 8g or 16g kit that works well in this model?
     

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  2. ilandmac macrumors member

    ilandmac

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    #2
    Hi,

    Most, if not all the third party offers will run much hotter but
    it should not affect the CPU temp.

    I've had good luck with the OWC ram but had to quick the exhaust
    fan an extra 200 rpm.

    And yea, the prices now on these is insane.
     
  3. reco2011 macrumors 6502a

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    May 25, 2014
    #3
    Amazon has 4 x 4GB DDR2 800MHz RAM for $228.00:

    16GB (4X4GB) NEMIX RAM Memory APPLE MAC PRO 2008 3,1 (2.8 3.0 3.2) (DDR2 800MHz PC2-6400 ECC FBDIMM)

    I purchased the DDR2 667MHz version of this memory (Nemix) for my Mac Pro 1,1 and I was very pleased with it.
     
  4. flowrider macrumors 601

    flowrider

    Joined:
    Nov 23, 2012
    #4
    My RAM Supplier:

    http://www.datamemorysystems.com/ap...-2-8ghz-ma970ll/a-early-2008-memory-upgrades/

    I have used these folks since 1985. They are Mac Specialists and their stuff is guaranteed for life. I have never received a bad RAM stick from them. There are more and more posts on this forum from folks trying to skimp on RAM, and IMHO, it's just not worth the hassle. Get quality stuff that's priced right at DMS.

    Lou
     
  5. macuser453787 macrumors 6502

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    #5
    Thanks for the tip. I will definitely keep DMS in mind. Question: Other than the fact that their RAM modules clearly cost less than OWC's, how would you rate them in comparison to OWC RAM? Just curious because at some point I'll be upgrading RAM in my cMP and would much rather pay less for comparable quality and performance.
     
  6. flowrider macrumors 601

    flowrider

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    Nov 23, 2012
    #6
    ^^^^IMHO, OWC is overpriced and their stuff is not well engineered. I just went through an SSD change on my MBA:

    As I said earlier, DMS's RAM us a top quality product with a Lifetime Warranty. OWC, on the other hand, not so much. You will have no issues if you use DMS RAM.

    Lou
     
  7. macuser453787 macrumors 6502

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    #7
    Thanks for the info. Just curious: Have there been other times that you've experienced a lack of good engineering in OWC products?
     
  8. flowrider macrumors 601

    flowrider

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    Nov 23, 2012
  9. 666sheep macrumors 68040

    666sheep

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    #9
    I put many of these in 2006-2008 MPs without a single problem:

    [​IMG]
     
  10. reco2011 macrumors 6502a

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    May 25, 2014
    #11
    I would recommend looking into the Nemix memory I mentioned above. The OP would save $48 over DMS, free shipping, no tax, and a lifetime warranty. I was very impressed with the memory for the money.
     
  11. omvs thread starter macrumors 6502

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    May 15, 2011
    #12
    Thanks - going to try some of the Nemix (2x4gb) and see how the machine reacts. While I agree with the sentiments about not cheaping out the ram in general,at some point it makes a lot more sense to get a new machine (or even a 2009/2010 model) and go with DDR3 instead.

    I've certainly seen lots of cases of flakey ram and such in my career - just never saw stuff that works, but caused the CPU temperature to sky-rocket. Then again, never had a FBDIMM machine either -- thank goodness.
     
  12. reco2011 macrumors 6502a

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    #13
    The suspect problem isn't bad RAM so much as it is not the correct RAM.
     
  13. omvs thread starter macrumors 6502

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    May 15, 2011
    #14
    Sure - but I wish I knew what wasn't correct. It was certainly advertised as for the Mac Pro, it had the big-*ss heat spreaders, and its a DDR2-FBDIMM w/ ECC.

    If it was just the memory running hot I could understand that. But heating up the CPU's just totally mystifies me -- even if the ram circuitry was screwed up (bad termination) I would think it'd cause the memory controller to heat up, not the CPU.

    Unless the ram somehow caused the SMC to get totally confused and started reporting incorrect results. Apparently the exhaust air was not very warm, which might support this. We debated using Mac Fac Control to override the two affected fans, but this seemed too risky long term.
     
  14. reco2011 macrumors 6502a

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    #15
    The 3,1 Mac Pro uses 800MHz DDR2 FB-DIMMs. Your OP stated you had installed 667MHz DDR2 FB-DIMMs. Unless you had installed the correct type of memory I wouldn't try to diagnose the problem as it could very well be the wrong memory.
     
  15. 666sheep macrumors 68040

    666sheep

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    #16
    If something is wrong with this memory, it isn't certainly the speed, it's rather temp sensors incompatible with MP firmware.
     
  16. omvs thread starter macrumors 6502

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    May 15, 2011
    #17
    Yeah, thats what I've concluded too. It'd be nice to know what would work before buying & trying, but at this point I don't see any alternatives.

    Thx to all!
     
  17. macuser453787 macrumors 6502

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    #18

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