How do I correctly apply thermal paste on a laptop CPU with a small surface area?

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I watched several videos on YouTube, went through a lot of overclocking forums and websites, but I am yet to find a "correct" answer to this question.

Some agree with the "pea method" where you apply a pea-sized glob onto the center of the CPU and then mount the heat sink over it and let the pressure of the sink spread the thermal grease evenly across the surface.

Others tend to gravitate towards the "business card method" of evenly spreading a thin layer of thermal compound across the CPU surface using a business card.

And then I read something about needing to apply more thermal compound to laptop CPUs because they don't have integrated heat spreaders.

I'm confused. I own a Acer 5542G notebook with an AMD Turion II X2 M500 CPU and ATI Mobility Radeon HD 4570 GPU. This computer has been overheating a lot lately (even playing Minecraft for a few minutes would trigger a system shutdown) and I just recently took it apart and cleaned it.

There was no dust accumulating on the fan grill, so I removed the thermal compound, cleaned the CPU surface and applied some new compound. I used the "pea method". My CPU has a rectangular surface so I applied two little pea-sized dots.

Where I used the thermal compound

After I did this, I ran CoreTemp and here's what I saw (idling temperatures): CPU running super hot!

That's a lot of heat! I'm guessing I screwed with my application of the thermal paste. I'm hoping anyone who owns an Aspire 5542G or a computer with an AMD Turion X2 M500 processor that has experienced the same problem could help me out here. Thank you.

Vinayak

Posted 2013-09-29T21:18:49.490

Reputation: 9 310

@DavidSchwartz How can you bend a heat pipe. I have an old laptop with bent heat pipes which doesn't heat up while my newer (2012) laptop with proper heat pipes overheats during a hangouts call (I haven't tried gaming and I don't play games) – Suici Doga – 2016-05-25T06:26:07.993

@SuiciDoga It's pretty easy to bend a heat pipe if the thing on one side of the pipe is "more stuck" than the other. I've seen it done more than once. And, sure, there are heat pipes that are properly bent at the factory and this allows them to fit without affecting them, but one accidentally bent and then bent back may fail to work properly, depending on the type of heat pipe it is and how badly it was bent. – David Schwartz – 2016-05-25T16:05:55.167

i do the credit card option, i dunno. Personally that pea sized amount doesn't look nearly enough for my liking. I generally put a layer as thin as i can, but across the whole die edge to edge. – Sirex – 2013-09-29T21:23:28.403

Does your notebook have an AMD CPU? Could you tell me what idling temperatures you get before and after you've applied the thermal grease? – Vinayak – 2013-09-29T21:32:53.193

my comment was in general, for any thermal paste i've ever done. My laptops have intels, though, which run at around 50 degrees - not entirely idle. I don't make the layer very thick, but two little dots of paste, i dunno. - Not convinced its enough. – Sirex – 2013-09-30T00:22:48.233

I first learned to to install CPUs before they had integrated heat spreaders (in fact, it was one of these). I didn't start using the credit card method until later, and I'm not convinced it's better. For what it's worth, I don't think 55C is that bad for a laptop (my old Athlon 3000+ idles at about 50C and I've never had overheating issues).

– user55325 – 2013-09-30T01:05:39.853

1yeah, i should state that spreading thermal paste is one of those topics which gets way more discussion that it needs. In my experience at least, sky high temps has never once been solved by one pasting technique over anouther. – Sirex – 2013-09-30T01:43:31.890

1Correctly re-attaching the heat sink on a typical laptop CPU is very complex. The heat pipes must not be bent, even a tiny bit, and the screws must be tightened in the correct order and to the correct tension. I would recommend letting a professional do it. – David Schwartz – 2013-10-01T07:13:19.587

1One other note -- despite being supposedly designed for the purpose, even the best "gaming" laptops should be run on an active cooling pad (that's one with fans) which will help substantially with keeping it at reasonable temps. Also if you mean that you checked the heatsink fins for dust, but you haven't checked all the air vents (ridiculously on the bottom most of the time) please also do the latter to ensure that air is blowing out of them. – Debra – 2013-10-01T12:23:51.607

Thank you for the suggestions. I did check the air vents and they're clean with no dust in them. Anyway, I disassembled my notebook again today and cleaned off the thermal paste that I applied earlier using the "pea" method and reapplied some new thermal paste (this one had greater viscosity) using the "business card" method and it's running WAY cooler now. The CPU now idles at around 65 degrees, almost 20 degrees cooler than the earlier 85. I also took some pictures of the CPU with new thermal grease applied to it and I'll add them to my answer. – Vinayak – 2013-10-02T15:32:16.630

@DavidSchwartz: I definitely tried getting this fixed at a service center but after 3 tries and no positive results, I thought maybe I'd take a shot at it. Regarding the heat pipes, I didn't touch them, but I noticed the pipes were at very close proximity to each other, almost touching. Could you maybe take a look at this picture and let me know if that's what the heat pipes should look like? http://imgur.com/7kkK6yS

– Vinayak – 2013-10-02T17:15:53.500

Answers

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Use a thin layer on very clean surfaces (alcohol is fine for cleaning, but let it dry before proceding). The thermal paste does not dissipate heat; its purpose is to put the CPU in close contact with the heatsink, so that the heat from the CPU transfers to the heatsink. So a thinner layer actually will work better & create a better seal between the two pieces of metal. The "pea", however, has to be put under great pressure to spread across the surface, and is less likely to keep the entire surface in good contact.

Also you might go for a better-quality paste, which can make a big difference. Thermal paste is something I never mess with going the cheapest, as even the "good stuff" is still usually around $10 or less (without using all $10 worth in one shot, too.)

If it is running too hot, it may mean that the CPU & sink are just not tightly enough meeting. You can often tell when you take it apart, too, because if the CPU lifts right off, there isn't much of a seal. Oddly enough, if the CPU is hard to get off, that usually indicates a better seal.

Debra

Posted 2013-09-29T21:18:49.490

Reputation: 4 000

4

As Debra and Sirex suggested, I decided to go with the "business card" method of application of thermal grease and this is what my CPU and GPU look like now:

Viscous thermal paste applied to CPU and GPU using "business card" method

After I reapplied the thermal grease, my computer's idling temperature dropped by almost 20 degrees and even under high load (I used Prime 95 for CPU stress testing) it wouldn't cross 90 degrees.

CoreTemp generated CPU temperature graph

Vinayak

Posted 2013-09-29T21:18:49.490

Reputation: 9 310

You Prime95 temperatures are good. But your idle is high (mine is 50 - 55C). My laptop has low idle (50 - 55C) and web (60 - 65) temperatures but gets up to 99C during a hangouts call. Prime95 will most likely cause my laptop to shutdown – Suici Doga – 2016-05-25T06:24:18.953

@SuiciDoga I know my idling temperatures are pretty high. The notebook is old and the AMD Turion processor in it always ran hot. These idling temperatures are the best it can do (at normal room temperature). – Vinayak – 2016-05-25T11:57:36.040

@SuiciDoga I'm not implying that AMD processors run hotter. I'm saying this particular Turion processor in my notebook was probably faulty and runs at a higher idling temperature than normal. – Vinayak – 2016-05-25T12:40:55.593

I meant old when i said low (I was typing from a tablet:). – Suici Doga – 2016-05-25T13:22:00.817

Old AMD CPUs weren't as good as now.And if you would like to know I have AMD A8-4500M – Suici Doga – 2016-05-25T13:22:23.007

Asked: 2013-09-29T21:18:49.490

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Active: 2016-03-03T20:33:39.330