iMac 5K - 4790K, M295X - thermal compound + second SSD upgrade

Discussion in 'iMac' started by AfroUSA, Jan 13, 2017.

  1. AfroUSA, Jan 13, 2017
    Last edited: Jan 13, 2017

    AfroUSA macrumors newbie

    AfroUSA

    Joined:
    Jan 9, 2017
    Location:
    UK
    #1
    Hi all!
    It was a pleasure to find this forum beginning of this year. I have iMac 5K with i7-4790K and m295X.
    After almost 2y of using this desktop, I stuck with unusual high temperatures for CPU and GPU.
    Idling with Chrome and YouTube, EyeTV, CPU was around 70 up to 102'C while gaming on Windows 10.
    GPU idling around 90 up to 105'C under heavy load on Windows (GTA V).
    It took me a over a month to figure out it must be old stock thermal compound or lots of dust.

    Well... It was both!

    This is what I found after opening iMac:
    [​IMG]

    1y 10m of using an iMac 5K we have this stuck on the fan:
    [​IMG]

    Stock thermal compound, was really dry. It looked and break like old fragile plaster :(
    [​IMG]

    CPU with stock compound
    [​IMG]

    GPU and SDRAM with stock thermal compound
    [​IMG]

    After cleaning with ArctiCleaner 1/2 and new GC-EXTREME compound. I used almost whole GC-Extreme 10g Thermal Compound (TC-GC-03-10g)
    [​IMG]

    On IFIXIT website they advice to stick this at the back to level the motherboard. But this is not necessary, as there are some level points at the back of the board and case.
    [​IMG]

    All stuck together with second SSD Crucial MX300 750GB. Spare for data.
    [​IMG]

    I did NOT peel the backing off the three sides, so only the bottom adhesive is holding the LCD to the iMac. I used four strips of adhesive transparent tape to temporarily hold the screen to the frame. Just in case something will go wrong in next couple of days.
    [​IMG]


    New stuff I bought for this job:

    1. iMac Opening Wheel Nylon Handle Complete Tool
    2. 2x Plastic Cards
    3. iMac Intel 27" EMC 2546 and EMC 2639 Adhesive Strips Strips only - 1 qty.
    4. iMac Intel 27" 5K Late 2014 and Mid 2015 Hard Drive Cable IF174-006-1
    5. OWC OWCDIDIMacHDD12 In-Line Digital Thermal Sensor for 27-Inch iMac 2012
    6. I had old 2.5" drive bracket from OCZ and spare Crucial MX300 750GB as a second drive for data

    - temperatures - After (left) - Before (right)
    [​IMG]

    At the end I would like to thank tubeexperience for help and answering my questions!
     
  2. steve23094 macrumors 68000

    steve23094

    Joined:
    Apr 23, 2013
    #2
    You mention max temps when gaming under Windows before you cleaned out and applied new thermal compound. What are the max temps you get under high load now?
     
  3. AfroUSA, Jan 15, 2017
    Last edited: Jan 15, 2017

    AfroUSA thread starter macrumors newbie

    AfroUSA

    Joined:
    Jan 9, 2017
    Location:
    UK
    #3
    Hi, now I have a fresh Windows 10 with BETA Driver Packaging Version 15.301.2101-160209a-299468C, playing GTA V 1.0.877.1 average is 85'C. Sometimes it can get up to 98'C but then fan will go mental and temp is quickly down to around 84-88 ;)

    What I noticed is how quiet iMac 5K can be. Before even just watching a YouTube video makes fan go crazy, up to 1800-2100rpm.

    15min playing GTA V
    [​IMG]
     
  4. macmee Suspended

    macmee

    Joined:
    Dec 13, 2008
    Location:
    Canada
    #4
  5. tubeexperience macrumors 68030

    Joined:
    Feb 17, 2016
  6. EnderBeta macrumors 6502

    EnderBeta

    Joined:
    Aug 5, 2016
    #6
    Do you think you could point out the poor cooling and solution to have AppleCare do preventative fixes on the hardware?
     
  7. macmee Suspended

    macmee

    Joined:
    Dec 13, 2008
    Location:
    Canada
    #7
    I was just going to ask, I wonder if I can ask the repair guys to slap some new thermal paste on everything, i will check
     
  8. dotnet macrumors 6502a

    dotnet

    Joined:
    Apr 10, 2015
    Location:
    Sydney, Australia
    #8
    I have no doubt that new thermal paste, properly applied, and a clean fan will improve the situation. A big part of the improvement you're seeing isn't real, though, but due to different loads during the before and after tests:

    [​IMG]

    Everything will obviously run cooler when the CPU uses only a third of the power, and the GPU 23% less. That's an extra 30W you didn't burn when you took the post-upgrade figures.
     
  9. mikeboss, Jan 16, 2017
    Last edited: Jan 16, 2017

    mikeboss macrumors 65816

    mikeboss

    Joined:
    Aug 13, 2009
    Location:
    switzerland
    #9
    you applied a ridiculous amount of thermal paste. WAY too much!!!

    EDIT
    and yes, just as "dotnet" mentioned: the before and after temps are totally useless if the CPU consumes three times the power during the "before" readings...
     
  10. AfroUSA thread starter macrumors newbie

    AfroUSA

    Joined:
    Jan 9, 2017
    Location:
    UK
    #10
    Hi,
    Maybe this will help, I'm watching 2 YouTube Videos - one to check burn of CNN on LCD, other in HD 720 to put some load on CPU. Fan is still on ~1202rpm. Temps and load below.

    This is what I got:
    [​IMG]

    I can confirm temperature is much lower with new thermal compound and clean fan :D


    After 8min I don't see any CNN on my screen, but after 40min on Windows, than back to macOS I have this:
    [​IMG]

    [​IMG]
     
  11. macmee Suspended

    macmee

    Joined:
    Dec 13, 2008
    Location:
    Canada
    #11
    Thanks so much for doing that test for me man, I appreciate it.

    It's crazy...... that retention have is even in the same spot as where it appears on mine, on the right side!
     

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