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NowIAmEuphoric

macrumors newbie
Original poster
Dec 30, 2019
4
0
Hello,

I have a "Macbook Pro 15-Inch Mid-2012 Retina" Model.


It's lagging due to CPU throttling under "heavier loads"(evident by very high kernel_task cpu usage in activity monitor, and high temp to the touch and monitored on SMC fan control).


The only way I can get around this is essentially using the computer for music and web browsing. Anything beyond that doesn't work well unless cooled by an icepack, or perhaps being in a cold environment.


I'd like to fix this, because before this issue started, this computer worked fine for me, and there would be a lot of money lost with minimal utility gained by upgrading to a newer macbook pro, aside from that I can't really afford one anyways.

I've tried a clean install, resetting the SMC and NPRAM, trying to blow some dust out from the outside, but nothing has helped.

At this point, it seems like I will need to open it up, try to remove dust from the fan systems with a air blower + clean the CPU & GPU, re-applying thermal paste on both.
I've never done anything quite this hands on before, (experience limited to GPU/RAM/HD stuff in iMacs/MacPros) but I'm confident I can do it. That being said, I will need to order some parts and commit to risking breaking my laptop, so I'm just looking to get some insight or advice before I do so.

Has anyone had an overheating issue like this on their macbooks pros, and managed to fix it? Is cleaning dust + reapplication of thermal paste likely to fix my laptops issues or is it likely to be something else?
Any other insight into my situation?

Cheers!
 

Webster's Mac

macrumors 6502
Dec 18, 2016
327
282
Hello,

I have a "Macbook Pro 15-Inch Mid-2012 Retina" Model.


It's lagging due to CPU throttling under "heavier loads"(evident by very high kernel_task cpu usage in activity monitor, and high temp to the touch and monitored on SMC fan control).


The only way I can get around this is essentially using the computer for music and web browsing. Anything beyond that doesn't work well unless cooled by an icepack, or perhaps being in a cold environment.


I'd like to fix this, because before this issue started, this computer worked fine for me, and there would be a lot of money lost with minimal utility gained by upgrading to a newer macbook pro, aside from that I can't really afford one anyways.

I've tried a clean install, resetting the SMC and NPRAM, trying to blow some dust out from the outside, but nothing has helped.

At this point, it seems like I will need to open it up, try to remove dust from the fan systems with a air blower + clean the CPU & GPU, re-applying thermal paste on both.
I've never done anything quite this hands on before, (experience limited to GPU/RAM/HD stuff in iMacs/MacPros) but I'm confident I can do it. That being said, I will need to order some parts and commit to risking breaking my laptop, so I'm just looking to get some insight or advice before I do so.

Has anyone had an overheating issue like this on their macbooks pros, and managed to fix it? Is cleaning dust + reapplication of thermal paste likely to fix my laptops issues or is it likely to be something else?
Any other insight into my situation?

Cheers!
I'd open the bottom panel and clean it with compressed air. You can't fully clean it without taking the bottom panel off due to the way the cooling system is designed. You may want to consider replacing the thermal paste as well. I'd be curious to see what your temps are. Install iStat Menus from the link below and post a screenshot of the sensor read out (be sure it's set to Celsius).
 
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leman

macrumors Core
Oct 14, 2008
19,318
19,333
It's lagging due to CPU throttling under "heavier loads"(evident by very high kernel_task cpu usage in activity monitor, and high temp to the touch and monitored on SMC fan control).

How do you know that it is not the other way around? That is, some rogue process/misconfiguration could be causing high kernel_task usage, which in turn occupies a lot of CPU and leaves little computational resources for the rest — hence the lag? Please check Intel Power Gadget — if you consistently see high CPU power consumption there, then that is much more likely to be the issue.
 

Webster's Mac

macrumors 6502
Dec 18, 2016
327
282
How do you know that it is not the other way around? That is, some rogue process/misconfiguration could be causing high kernel_task usage, which in turn occupies a lot of CPU and leaves little computational resources for the rest — hence the lag? Please check Intel Power Gadget — if you consistently see high CPU power consumption there, then that is much more likely to be the issue.
Kernel_task is used to throttle back the CPU due to heat. See here: https://support.apple.com/en-us/HT207359
 

klagermkii

macrumors member
Mar 15, 2007
84
123
Has anyone had an overheating issue like this on their macbooks pros, and managed to fix it? Is cleaning dust + reapplication of thermal paste likely to fix my laptops issues or is it likely to be something else?
Any other insight into my situation?

Cheers!

I had overheating and had pretty good experiences with cleaning the fans: https://forums.macrumors.com/thread...nts-of-an-older-rmbp-can-really-help.1941864/

I'd hesitate to go down the whole re-pasting route unless you're positive that's the problem. These laptops will throttle both if the CPU can't get the heat to the heatpipe (i.e. needs new thermal paste) but also if the radiator can't vent the heat out the system (i.e. fans/vents clogged).

The icepack thing makes it sound like the vents are clogged more than the CPU. You can check it by firing up Intel Power Gadget or iStat or anything like that, run some CPU stress tool for a few minutes, and then see if the CPU is still at 100 celsius/212 farenheit. If the CPU temperature has fallen below 100 celsius, then it's being throttled because the case of the machine has got too hot (poor airflow). If the CPU temperature is at 100 celsius, then it's throttled because it can't get heat away from the CPU and maybe the re-pasting will help.
 

NowIAmEuphoric

macrumors newbie
Original poster
Dec 30, 2019
4
0
Hello all.

I have opened her up, cleaned the crusty thermal paste off from the chips & heasink, replaced the thermal paste, as well as cleared out the fans from dust as well as I could. There was a lot of dust, and the thermal paste was very crusty..

Results: temperatures seem to be lower. Previously I would reach 100 when under full load, but now I'm closer to 80 under full load. And I haven't noticed kernal task taking up nearly as much as it did in the past.

One thing I did notice however... I ran Geekbench 4, and came up with a score of 5164 on multicore.
This seems like the computer is still having speed issues as this is half of the quoted amount this computer should be getting as per "https://everymac.com/systems/apple/...-i7-2.3-15-mid-2012-retina-display-specs.html".

So it seems like the lag may be something else.. Is it normal for a computer to be slowed down this much from it's quoted speed?

Cheers.
 

klagermkii

macrumors member
Mar 15, 2007
84
123
Seeing a lower temperature like 80 degrees could be good or bad. Good if it's cooling well and getting rid of all the heat, bad if it's throttling somewhere else that is limiting the CPU to that temperature.

Get Intel Power Gadget and check the sustained power used by the CPU during your multicore Geekbench run. You should be seeing 35W+ of power used on that multicore test and the CPU frequency should stay above the 2.3GHz base clock.

If you aren't seeing that you probably still have thermal problems.
 

NowIAmEuphoric

macrumors newbie
Original poster
Dec 30, 2019
4
0
Seeing a lower temperature like 80 degrees could be good or bad. Good if it's cooling well and getting rid of all the heat, bad if it's throttling somewhere else that is limiting the CPU to that temperature.

Get Intel Power Gadget and check the sustained power used by the CPU during your multicore Geekbench run. You should be seeing 35W+ of power used on that multicore test and the CPU frequency should stay above the 2.3GHz base clock.

If you aren't seeing that you probably still have thermal problems.

Hmm, it seems to have quite a range in both voltage and frequency, it's certainly dipping well under the base clock and power usage, but also hitting normal highs.
Do those power and frequency charts look normal to you?
It's very strange because this Geekbench test this morning DID get 11000 on the MC score. Literally twice as much as it did last night when I ran multiple tests hitting around 5100...
 

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impulse462

macrumors 68020
Jun 3, 2009
2,089
2,874
Hmm, it seems to have quite a range in both voltage and frequency, it's certainly dipping well under the base clock and power usage, but also hitting normal highs.
Do those power and frequency charts look normal to you?
It's very strange because this Geekbench test this morning DID get 11000 on the MC score. Literally twice as much as it did last night when I ran multiple tests hitting around 5100...
removed
 
Last edited:

klagermkii

macrumors member
Mar 15, 2007
84
123
Hmm, it seems to have quite a range in both voltage and frequency, it's certainly dipping well under the base clock and power usage, but also hitting normal highs.
Do those power and frequency charts look normal to you?
It's very strange because this Geekbench test this morning DID get 11000 on the MC score. Literally twice as much as it did last night when I ran multiple tests hitting around 5100...

Well 11000+ does sound right.

It's a bit hard to tell with Geekbench as it's so "bursty" in terms of CPU, so you never really get to see what it's properly stressing. I'm surprised there is no point in the graph where it goes significantly over 35W. I've attached my graph from the same test (2012 rMBP i7-3720QM).

1578526353169.png


I would recommend trying something like Prime95 which solidly stresses your CPU and makes a much clearer graph as to where the maximum temperature/frequency is.

1578526532787.png
 
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