Help: Why is my OWC RAM running so hot & fans not helping

Discussion in 'Mac Pro' started by firstyearprof, Feb 15, 2008.

  1. firstyearprof macrumors member

    Apr 16, 2007
    Hi all:

    My OWC RAM is working just fine, but I am growing increasingly concerned about the temperatures at which it runs. I have the 3.0 (120W) MacBook 2008 with 18 Gb RAM (4x4Gb + 2x1Gb apple stock). The RAM in memory module A2 & B2 is getting up to 80 Celsius without even much of a workout on the RAM. What's more, the MacPro fans are not increasing - right now the hottest module is at 76 Celsius and fans haven't increased at all (see screenshot below).

    I have installed SMC fan control, which I understand is supposed to set the MINIMUM fan speed, which I have set at 730 because my RAM was running hot even without any workout.

    How concerned should I be about this? Is this a) a defect in my mac pro b) a design flaw c) a problem with OWC memory, or d) is everything OK and I'm making a mountain out of a molehill?

    Thanks for any help!

  2. Mr.PS macrumors 6502a

    Jan 8, 2008
    The bottom riser gets hotter naturally. Read the threads that larry from OWC replied too.
  3. firstyearprof thread starter macrumors member

    Apr 16, 2007
    Thanks for the help. I did read OWC Larry's responses. He says that these modules are rated UP TO 190 F. My modules right now are 173 F, with hardly being put under any stress. That's a bit close for comfort. Is this not something to worry about?

    Unfortunately, Larry never directly addressed this issue in the thread. He said that 70C = 120 F (or thereabouts), and that "this is well within specs". But as another poster said, his math was WAY off; 70 is about 160 F. He didn't respond again that I can see...
  4. aibo macrumors 6502

    Jan 17, 2008
    Southern California
    even still, his modules are running hotter than your average Mac Pro's.
    here are my current temps

    i'm going to guess you just got some unlucky RAM.
  5. Mr.PS macrumors 6502a

    Jan 8, 2008
    Here are my stats:


    Looks like the OP got some bad ram, my room is pretty hot 73F or so and the ram is normal temp wise.
  6. Mr.PS macrumors 6502a

    Jan 8, 2008
    So are our temps far off normal? I don't think they are... OWC ram only run 3-4 degrees warmer for me, which makes sense since it's on the bottom riser which gets slightly less airflow.
  7. eyecool macrumors regular

    Jan 11, 2008
    Fort Worth, TX

    Attached Files:

  8. Mr.PS macrumors 6502a

    Jan 8, 2008
    how about some numbers in Celsius? ;)
  9. kirkbross macrumors 6502a


    Mar 6, 2007
    Los Angeles
    How did you fit 18GB of RAM into a Macbook?
  10. firstyearprof thread starter macrumors member

    Apr 16, 2007
    Doh... I meant Mac Pro obviously. Anyway, i've bumped the fans up to 950rpm. The hottest one is now running at 150 F under zero work strain.

    So I sure wish someone could give me some confirmation. Where's OWC Larry? Is this probably an issue of bad RAM? If so, I guess I have to wait until it goes bad before returning it?

    My guess is that this is an Apple design flaw. My modules are 4GB each, which are hotter than any other RAM. I have four together now + 2 1GB modules. If my RAM is normal and any indication, then when you put 8 4GB in a 120W machine, the temps are going to get too hot. My bet is that over the next year we'll start hearing about this issue. I find it very troubling that the Apple fans aren't increasing, even at temps around 170 F.

    Can anyone confirm the temp at what RAM begins going bad? And can anyone else who has a 3.0 or 3.2 with 4GB modules confirm their temps? If everyone's getting readings this hot and indeed RAM isn't supposed to go over 180 F, then boy oh boy, this is not good.
  11. GregPacker macrumors member


    Jun 27, 2007
    Wherever there is a queue
    I found that oversight concerning too. I was about to order some OWC RAM but paused when I read that.
  12. scottydawg macrumors 6502


    Jan 22, 2008
    Sacramento, CA
  13. Mr.PS macrumors 6502a

    Jan 8, 2008
    I have no connection with OWC - for the record. I am running 2x2gb sticks from them and they work flawlessly. Temps are maybe 2-3C more then stock, sometimes 1-2C less. I wouldn't think twice about re-ordering... Those seeing high temps, RMA them, if not, buy else where. What else can you do?
  14. phjo macrumors regular

    Jan 8, 2008
    I have the same concerns than you do, and I would like to read larry from OWC again on that subject. (I hoped he might answer specifically my question from the thread : but maybe he just didn't see it...)

    As for the fans not speeding up, in my experience they do (a bit) ! But smc is waiting for very high temperatures (above 75°C) to boost them up (you can observe this by going back to minimal speed to default and monitoring the fans with istat pro : they will go up for a few seconds, then down again...)

    I am not confortable with the standard minimal speeds when the mac pro is at high load so I bumped them a bit, but the temperatures you cite are obviously quite a bit higher than mine, so you need higher speed than I do...

    (Again, Larry from OWC could enlighten us about the temperatures the dimm could sustain for a long time without damage...)

    As you do, I would tend to believe those higher temperatures are not a default per se of the dimms, but rather of inadequate cooling for such a configuration...

  15. Pressure macrumors 68040


    May 30, 2006
  16. wpattison macrumors member


    Jan 21, 2008
    San Francisco, CA
    Pardon my ignorance, I'm soon to be a new Mac Pro user. But could you just swap the stock RAM to the lower riser, and the OWC RAM to the upper riser, and see how the temps work out?
  17. Mr.PS macrumors 6502a

    Jan 8, 2008
    Good question!
  18. Volante macrumors regular

    Feb 8, 2008
    What's the application/widget that shows memory temperature in celsius in the first post?
  19. Mr.PS macrumors 6502a

    Jan 8, 2008
    google istat, it's istat pro.
  20. fandsw macrumors regular

    Oct 24, 2007
    Helena, AL
    iStat app!
  21. orpheus1120 macrumors 65816


    Jan 23, 2008
    We can go a step further to isolate the problem by taking out the OEM rams, and just running the OWC ones. From there, monitor the temperature reading again for each memory module to determine temperature differentials between top and lower risers.

    If I'm doing it, I will try to find out if there's a faulty ram present or test the theory of lower riser's temperature to be generally higher than the upper by doing this:-

    1) Take out OEM ram.
    2) Take note of each 4GB-module Dimms that goes into each memory module and monitor the temp readings.
    3) Swop them around (top risers -> lower risers and vise versa etc) to determine if a faulty ram is present.

    If readings for the particular memory module(s) after the swaps are still abnormally high, changes are the RAMs are fine, and the problem may be due to the MP hardware.
  22. phjo macrumors regular

    Jan 8, 2008
    My guess is we wouldn't see a significant change, and that memory modules A2 and B2 would still be the hottest, all the more when there is memory dimm in A3 and/or B3...

    (It makes sense they are the hottest when there is something in A3, but when there is nothing, maybe the sensor location on one or another side of the dimm could explain the difference ?)

    Well, the question still stands : are those temperatures abnormally high ?

  23. junior77 macrumors regular

    Jun 29, 2007
    Can someone help me clarify what the different memory locations refer to? i.e, A1 vs B1, memory module vs. memory bank?
  24. firstyearprof thread starter macrumors member

    Apr 16, 2007
    Someone asked "if it doesn't crash, why worry?" That's like asking "so what there's a loud knocking sound when you drive your new car - why worry if the car still drives?" :rolleyes:

    So I've been running my 18GB RAM pretty hard for about an hour straight. The temps got up to 176F and then plateaued, and the Mac Pro fans FINALLY turned on, anemically (they went up by 100rpm). So should I assume that the Mac Pro designers feel like 176F running RAM is just fine, or is there a problem with my RAM, or with the MacPro design when run with 4GB modules?

    In other words, my question for folks out there still stands: does anyone know if RAM running at 176F is OK?

Share This Page