In Middle of NB heatsink repair: have Q

Discussion in 'Mac Pro' started by adam9c1, Oct 20, 2015.

  1. adam9c1 macrumors 68000


    May 2, 2012
    I was seeing very high NB temperatures.
    When I purchased the cMP I was told one of the clips was replaced with a bolt.

    I have removed the two CPUs and found the one original clip broken and the heatsink was loose.

    I have ordered what looks like the (based on the name) correct replacement heatsink mount clips from eBay however they are much larger.

    Please see the attached photo:
    L: metal bolt (no nut, I think the previous owner had to tap the cpu tray)
    C: original clip broken off
    R: new eBay replacement clips

    When I install them do I need to mod them?

    Attached Files:

  2. ActionableMango macrumors G3


    Sep 21, 2010
    The owner in this thread replaced his successfully.

    Yours looks roughly the same size, but it can be really hard to tell. There's a picture in that thread where he has measured it with a ruler. You could measure yours and compare.
  3. adam9c1 thread starter macrumors 68000


    May 2, 2012
    Ended up using NB pins from a old motherboard.
    I can power up the unit (at post I have one red light blink, don't know if that's normal or not).

    I load up to the desktop and fire up Temperature Gauge Pro.
    All temps look like before (except for the NB which is at 43*C) but fans are 3/4 of their speed.
  4. adam9c1, Oct 20, 2015
    Last edited: Oct 20, 2015

    adam9c1 thread starter macrumors 68000


    May 2, 2012
    Command Option P R

    system sitting idle for few minutes
    CPU A Diode 39
    CPU B Diode 30
    CPU A HS 37
    CPU B HS 29
    CPU A Core 54
    CPU B Core 61
    NB Core 66
    NB HS 56

    I will let the machine sit at idle more tomorrow and install the rest of RAM.

    Are these numbers good?
    Before my NB HS would sit at 30 (but it was not touching the chip) so the increased temp now makes sense.

    I hope these numbers look good and the clips I used from another main board hold up.
    They were not brittle and rather easy to remove (pressed in a little with pliers then pushed out)

    The HS has some wiggle to it, I mean I can move it by hand so I think it's a little loose.
    Not sure what is normal.

    After few minutes of running TG Pro and manually pushing fan speeds at 10%
    NB Core 60*C
    NB HS 50*C
  5. TzunamiOSX macrumors 6502

    Oct 4, 2009
    For a dual, 60°C is pretty normal. I have 66°C on normal use. I'm not sure, but perhaps the NB is handling the communication between the two CPUs.

    Fact: Temp is much lower with a single CPU.
  6. h9826790 macrumors G5


    Apr 3, 2014
    Hong Kong
    Those numbers are very good, nothing to worry about. If you really want to test it, do some simple job. The idea is to stress the NB, but not the CPU. If you put 100% loading to the CPU, the fan will spin up, which will cool down the NB very effectively.

    So, do some job use 2-3 cores usually will keep the fan at idle but stress the NB a bit. Even though the limit of NB is above 100C, but it seldom go above 85C (in a very hot day, no air con, fan at idle, etc).

    From your number, it may go up to around 75C when stressed, but that's completely normal and well within limit.
  7. Lucas Godfrey macrumors 6502

    Lucas Godfrey

    Jul 12, 2010
    Somewhere between Here and There
    Just do what i did, get some thermal epoxy, mix it up and glue the heatsink back on. temps were lower then before and theres no more "pins/clips" to break and possibly fry the northbridge down the line.

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6 October 20, 2015