Early '08 15" GPU Temperatures

Discussion in 'MacBook Pro' started by bunnspecial, May 5, 2015.

  1. bunnspecial macrumors 603

    bunnspecial

    Joined:
    May 3, 2014
    Location:
    Kentucky
    #1
    I bought one of the above computers not too long ago-it was cheap, and I wanted a 15" Intel Mac to finish up work on my master's thesis.

    In any case, I know that these have known GPU issues that-from what I've read-seem to be heat related.

    I installed "Macs Fan Control" and had it tie the fan speed to the GPU temperature. It will start to increase the fan speed(both fans) when the GPU hits 100ºF, and will hit the fan maximum speed when the GPU hits 130ºF.

    So far, it seems to at least be keeping the temperature under 130ºF(it's at 126º at the moment). I'm still wondering if this is on the warm side, though.

    As a secondary question to that, with a GPU temperature of 126º, the heatsink is at 109ºF. In addition, the CPU is running at 109ºF with the heatsinks around 100º.

    I'm guessing that the temperature difference is indicative that I need to do a repaste. Looking at the iFixit guide, I don't think it's anything beyond my skill level, but also don't want to attempt it until I'm completely finished with my thesis(which will hopefully be tomorrow).

    Does anyone have any thoughts or information about what would be "dangerous" temperatures for the GPU? In addition, with the discrepancy in GPU and heatsink temperature that I'm seeing, should I take the time to repaste it?
     
  2. snaky69 macrumors 603

    Joined:
    Mar 14, 2008
    #2
    130F(seriously, when will the US stop using the retarded imperial system and get with the times?) is barely warm for a GPU. Those puppies will easily reach up to 105C (I'll let you do the math).
     
  3. Samuelsan2001 macrumors 604

    Joined:
    Oct 24, 2013
    #3
    It's a cheap.....

    ...Second hand computer that is 7 years old, dude, it will fail when it fails and that could be now or in 2 years time and at that age there is pretty much nothing you can do that'll make it less likely.

    By the way those temperatures are very low....
     
  4. bunnspecial thread starter macrumors 603

    bunnspecial

    Joined:
    May 3, 2014
    Location:
    Kentucky
    #4
    I'm sorry that my use of the standard temperature units for my country offended someone in this thread.

    In any case, I wanted to report that after repasting the CPU and GPU with AS5 and doing a general clean-out of the system, the GPU temperature has decreased.

    And, since we're going to be pedantic about temperature units, I'll just mention that the temperature under light usage is about 586ºR and maybe pushes 590ºR under heavier use. For those of you who prefer your absolute temperature units in the SI system, that's about 325K at the low end to 327K at the high end.

    Also, even though it may be a 7 year old computer, I still want to get as much life out of it as I can, and keeping temperatures down(especially on a computer with known GPU issues) is the best way I know to do this. I still use older Macs than this on a daily basis, and have just spent a week doing almost everything on a Powerbook G4 and PowerMac G4.
     
  5. snaky69 macrumors 603

    Joined:
    Mar 14, 2008
    #5
    Still running quite cool, though it doesn't seem like your temperatures have moved all that much. Isn't 586R pretty much the same as 130F? I would've hoped for better.

    It wasn't a jab at you personally, nor was I offended. But as a non-American, it gets old real fast having to convert units all the time for posters than come from one of the only 3 countries left in the whole world that still use the imperial system.
     
  6. bunnspecial thread starter macrumors 603

    bunnspecial

    Joined:
    May 3, 2014
    Location:
    Kentucky
    #6
    When pushing it before, it would hit 140ºF(~50ºC, 333K, 600ºR), although 136ºF was a normal temperature.

    Now, the temperature rarely goes above 130ºF, and the temperature under light use stays around 120ºF. That may not be a huge improvement. I've also noticed that the temperature seems to drop a degree every couple of days, so I may not have hit the advised 200h "cure time" of AS5.

    Like most old laptops, though, the paste really was shot. It took me a while to clean it all out, and I ended up taking the logic board and heatsink into work and using a plastic lab spatula(along with compressed air) to get all the old paste off. I also found myself needing to use more "potent" solvents than I have at home(namely hexane, absolute ethanol, and 100% isopropyl alcohol) to get everything off.
     
  7. Queen6 macrumors 603

    Queen6

    Joined:
    Dec 11, 2008
    Location:
    Putting out the fire with gasoline...
    #7
    Key with these early 2008`s is to keep the GPU below 70C, it`s at that point and beyond the Nvidia GPU is damaged due to the poor manufacturing process. elevating the Notebook on an aluminium passive cooler also helps to reduce operating temperatures further.

    FWIW I still have an early 2008 pre unibody, still running on all the original components albeit pretty much returned these days. Mine ran for literally years close and above 70C, equally it was rarely shutdown or restarted which helps to reduce any thermal shock, which is what kills these GPU`s in quicktime...

    Q-6
     
  8. bunnspecial thread starter macrumors 603

    bunnspecial

    Joined:
    May 3, 2014
    Location:
    Kentucky
    #8
    Thanks for some concrete numbers on what to look out for.

    I'm using SMC Fan Control, and have the fan speed tied to the GPU temperature. The fans are set to run full blast at 150F(65C)(sorry, I'm typing from my iPhone and can't find the degree symbol-I miss option-0) but have yet to have it get that hot.
     
  9. Queen6 macrumors 603

    Queen6

    Joined:
    Dec 11, 2008
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    Putting out the fire with gasoline...
    #9
    Yeah 70C (158F) is the point at which the risk increases, it`s all tied to the the change over in the industry to lead free solder. Rapid heating and cooling cycles should be avoided as this related directly to Thermal Shock which is frankly the killer of many MBP`s with discrete GPU`s.

    Elevating the rear of the Notebook and increasing fan RPM`s is about as much as you can practically do, after that you need to look at reducing the load applied by software. External powered cooling pads don't do much in my experience with Mac`s if they do have a significant airflow it can help to reduce the the internal fan RPM`s, however generally the component temperatures remain the same.

    I never upgraded past 10.6 nor repasted my Early 2008 as it`s thermal envelope has always remained stable. I did clean out the cooling system and replace both fans about 3 years back, they are starting to become a little loud again and the battery finally died late last year, equally the system has more than paid for it`s self and replaced by far more powerful Mac`s...

    Given the Notebooks`s usage and uptime tremendous value for money :)

    Q-6
     
  10. Idefix macrumors 6502

    Joined:
    Jul 10, 2012
    #10
    I've used a laptop cooler with my 2008 MBP. The trick is to find a cooler that has fans blowing upwards at the bottom of the laptop. You're essentially cooling the skin of the MBP.

    Coolers that drag air away from the laptop are worthless. Not enough cooling.

    You still have to use smcFanControl in conjunction with the cooler--it's nice to have both when the laptop is doing some heavy lifting.
     
  11. cookies! macrumors 6502

    Joined:
    Jul 3, 2011
    #11
    I remember my old '08 MBP and that thing made me SWEAT. I'm pretty sure it came close to burning my thighs too. And the GPU eventually kicked the bucket, undoubtedly from the heat. Keep that sucker cool!
     
  12. bobbytomorow macrumors 6502

    bobbytomorow

    Joined:
    Nov 10, 2007
    Location:
    Left Coast
    #12
    I'd disassemble it and drill some holes were the intake fans are
     
  13. wksj macrumors member

    Joined:
    Feb 20, 2015
    #13
    Are you saying that 55C is too hot? What do you want, room temperature? And CPU at 40C... I won't even reply to that. (rounded numbers)
     
  14. bunnspecial thread starter macrumors 603

    bunnspecial

    Joined:
    May 3, 2014
    Location:
    Kentucky
    #14
    I don't know why I keep dragging this thread back up, but wanted to reply to this.

    I now have a good answer that I should be worried about GPU temperatures approaching 70ºC.

    On an older computer that is known to have GPU problems related to high temperatures, I don't think this is an entirely unreasonable discussion.

    And, yes, it's a 7 year old computer, but I'm not a fan retiring things based on age alone. There's nothing I do with a computer which this computer is not capable of doing-and it's even plenty fast for my purposes at that. In real world use, I usually don't notice it being slower than my 13" i5 MBP with 8gb of DDR3 RAM, and more efficient productivity I get from a 15" screen makes up for the fraction of a second longer that it may take to do some operations faster than my newer 13" MBP.
     

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