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[RESOLVED] Shimming a laptop heatsink

Posted: Tue Mar 12, 2019 6:11 am
by Jay_H
Hey everyone, you're the most knowledgeable bunch of folks I know regarding computers, so I figured I'd try here. I just obtained the most powerful laptop of my life, which is like 3x faster than what I used to run. All the games that stuttered for me are now loading instantly, including DFU. The problem is that the CPU idles between 60C and 70C and sometimes tends toward 85C under heavy load. It was apparently made with a design defect that stores heat.

I'm planning on putting in a copper shim with some thermal paste and glue, which I'm reading is an effective countermeasure. Anyone have any experiences with it, or any advice to give before I do it on Thursday?

Re: Shimming a laptop heatsink

Posted: Tue Mar 12, 2019 9:49 am
by jayhova
In the realm of thermal compound the secret is to have just enough and no more. Remember that some of these compounds are conductive and can cause problems if the paste gets into the wrong location. You'll need enough to get a thin even layer that allows for heat to be conducted. Bear in mind the paste will not conduct as well a the metal you are putting it on but it does conduct far better than air.
  • Before you do anything, get a baseline for how things are working by running something like prime95 and looking at your temps after 10-15 mins.
  • Start by making sure your parts are reasonably clean.
    [youtube]https://www.youtube.com/watch?v=x9MJUuU58vE[/youtube]
  • Check to see if the problem you are having is caused by simply not having good thermal contact between your CPU and the heatsink
  • Apply a small bead of paste to the processor and press your clean heatsink back into place and reassemble and test using prime95 and compare to your baseline
  • Once you have an idea of how much improvement your fresh application of paste created, disassemble and inspect your work from the previous step. If done correctly the paste should have spread in a thin layer completely or near completely covering the processor with only a small amount squeezed out on the sides. If the paste is thin but not covering you used too little. if significant amounts ejected out the sides you have used too much. Adjust the next step accordingly. If the paste had not spread very thinly this may be a sign that you do not have enough clamping pressure;hence the shim.
  • install your shim by securing it to either the heatsink or the processor with the proper amount of paste.
  • Apply paste to either the top of the shim or the processor depending on which is exposed and reassemble,
  • Finally, test again to check your results.
Bear in mind that a layer of thermal paste is a point of failure. Generally good quality paste like arctic or similar, will often resist premature failure better than OEM pastes. If installing the shims does not significantly improve heat control, it may not be worth it to double your points of failure. In any case monitor your heat control over the next few months to insure it is not drifting.

Note: the use of the term CPU and processor apply to GPUs as well.

Re: Shimming a laptop heatsink

Posted: Tue Mar 12, 2019 2:08 pm
by Jay_H
Fantastic. Thank you for the guidance :)

Re: Shimming a laptop heatsink

Posted: Tue Mar 12, 2019 7:12 pm
by Feralwarlord
jayhova wrote: Tue Mar 12, 2019 9:49 am In the realm of thermal compound the secret is to have just enough and no more. Remember that some of these compounds are conductive and can cause problems if the paste gets into the wrong location. You'll need enough to get a thin even layer that allows for heat to be conducted. Bear in mind the paste will not conduct as well a the metal you are putting it on but it does conduct far better than air.
it's better to have to much than not enough as any excess will get forced out the sides of the heatsink, which is infinitely more preferable to overheating, well as long as your choice of thermal paste is non-conductive anyway. (note this does not apply to liquid metal)

also jay idk what the processor in your laptop is but for higher end laptop cpu's 85C under load is a pretty good temp and your high idle temps may be caused by the fans in the laptop not turning on until the cpu hits 75C or something to make it more quiet, although since you haven't said what your laptop is I'm just making assumptions here.

Re: Shimming a laptop heatsink

Posted: Tue Mar 12, 2019 7:15 pm
by Hazelnut
FWIW I use acetone (plain nail polish is easiest way to obtain) to clean a cpu for new thermal paste applications. Remember not to contaminate with grease from bare fingers. Also bear in mind that the paste is intended to fill in minute microscopic unevenness of the surfaces... so you really don't need a lot.

Good luck, I've taken a laptop apart before - an old one - and it was quite like performing surgery. Make sure you have the full disassembly guide/instructions to hand. Videos of people doing this is also very helpful.

Re: Shimming a laptop heatsink

Posted: Tue Mar 12, 2019 7:21 pm
by Feralwarlord
Hazelnut wrote: Tue Mar 12, 2019 7:15 pm FWIW I use acetone (plain nail polish is easiest way to obtain) to clean a cpu for new thermal paste applications. Remember not to contaminate with grease from bare fingers. Also bear in mind that the paste is intended to fill in minute microscopic unevenness of the surfaces... so you really don't need a lot.

Good luck, I've taken a laptop apart before - an old one - and it was quite like performing surgery. Make sure you have the full disassembly guide/instructions to hand. Videos of people doing this is also very helpful.
isoproply alcohol is also good if you have it.
Using a guide is a good idea but in general don't try to force anything and be wary of hidden screws (looks at HP)

Re: Shimming a laptop heatsink

Posted: Tue Mar 12, 2019 7:23 pm
by Feralwarlord
Also look and see if your laptop has a service manual available online

Re: Shimming a laptop heatsink

Posted: Tue Mar 12, 2019 10:57 pm
by jayhova
Feralwarlord wrote: Tue Mar 12, 2019 7:12 pm
it's better to have to much than not enough as any excess will get forced out the sides of the heatsink, which is infinitely more preferable to overheating, well as long as your choice of thermal paste is non-conductive anyway. (note this does not apply to liquid metal)
True but only somewhat better. Remember these pastes are viscose and will resist being squeezed. In a laptop you will not have a lot of contact pressure (hence the initial problem). While these pastes are petty good at conducting they need to be only thin enough to eliminate any air gaps and maximize contact between surfaces. Since you are doubling the number of layers this becomes twice as important. Too much is better than not enough but just barely too much is best.

also my laptop is fine :-)

Re: Shimming a laptop heatsink

Posted: Wed Mar 13, 2019 12:06 am
by Jay_H
Feralwarlord wrote: Tue Mar 12, 2019 7:12 pm also jay idk what the processor in your laptop is
My readout says "Intel Core i7-4810MQ CPU @ 2.80GHz × 8." All I know is that runs like a rocket ship and cost me very little as refurbished, you folks will know whether it's good or not :lol:
but for higher end laptop cpu's 85C under load is a pretty good temp and your high idle temps may be caused by the fans in the laptop not turning on until the cpu hits 75C or something to make it more quiet, although since you haven't said what your laptop is I'm just making assumptions here.
This is a valid point; the fan sounds strong and goes pretty stably above 70C. What freaked me out was that I ran some Passmark software on it last night, and when most sensors went up to 93C, the CPU sensor failed completely and refused to return until I flushed the BIOS. I cut the test right there since I'm paranoid of any damage (the same thing happened today with the Prime test jayhova recommended). I haven't seen any actual throttling or any other signs of overheating but the readings seemed pretty excessive to me.
Good luck, I've taken a laptop apart before - an old one - and it was quite like performing surgery. Make sure you have the full disassembly guide/instructions to hand. Videos of people doing this is also very helpful.
Thank you, I may need the luck :) This is a step above what we've done so far; my wife transferred a bunch of memory from our old computers and switched over my HDD to this new one, but those are simple changes. This is a whole new chapter for us.
Check to see if the problem you are having is caused by simply not having good thermal contact between your CPU and the heatsink
What's a test for this? That sounds like something that'd be analyzed when the laptop is closed and functioning, so I don't know how to recognize this.

Re: Shimming a laptop heatsink

Posted: Wed Mar 13, 2019 12:33 am
by Feralwarlord
jayhova wrote: Tue Mar 12, 2019 10:57 pm
Feralwarlord wrote: Tue Mar 12, 2019 7:12 pm
it's better to have to much than not enough as any excess will get forced out the sides of the heatsink, which is infinitely more preferable to overheating, well as long as your choice of thermal paste is non-conductive anyway. (note this does not apply to liquid metal)
True but only somewhat better. Remember these pastes are viscose and will resist being squeezed. In a laptop you will not have a lot of contact pressure (hence the initial problem). While these pastes are petty good at conducting they need to be only thin enough to eliminate any air gaps and maximize contact between surfaces. Since you are doubling the number of layers this becomes twice as important. Too much is better than not enough but just barely too much is best.

also my laptop is fine :-)
well in direct die cooling (like in most laptops) it's alot more important to make sure the entire cpu has coverage compared to when it has an ihs but it's not like I'm recommending that you go completely overboard like the verge did