2018 MacBook Pro cooling mod

1096bimu

macrumors 6502
Original poster
Nov 7, 2017
319
291
I've alluded to this mod in an earlier post, I have since implemented it and used the moded machine for a while to form a mature opinion about it. I think this mode is great for people who regularly use their MacBook in clamshell mode although I cannot recommend it because it obviously voids warranty (but Apple doesn't have to know since it's non-destructive).

Pros for the mod:
  • non-destructive, completely reversible
  • relatively cheap, easy and safe to apply
  • does not significantly affect normal usage
  • up to 20 degrees lower temperatures under sustained load
  • reduced fan speed under such load, and therefore noise
  • higher sustained power under such load, up to 7W more power
  • can accept external cooling like heat sinks or ice packs for silent cooling even at max power
Cons:
  • can burn your skin if not careful
  • prohibits laptop use under high loads
  • potential damage to skins/cases/tables/table mats
  • thermal improvements are mostly negated when sitting flat on a surface
Theory

https://forums.macrumors.com/threads/im-thinking-of-a-thermal-mod-for-the-mbp.2133914/

As I have mentioned in this post, due to the proximity of the heat source and the bottom cover which is effectively a big radiator, we can simply couple them together and let the bottom panel radiate heat into the environment.

Screen Shot 2018-10-11 at 8.57.09 PM.png
Application

Quite simply, you remove the bottom cover, and apply 1.5mm thick thermal pad to the hottest areas like so:
DSC00801.jpg

The power regulators up top don't really need this because they can tolerate very high heat but I paded them anyway because they could offer better efficiency at lower temperatures and thus reduce power consumption.
DSC00802.jpg

And that's it, you just pop the cover back on and you're good to go. Except for the bottom cover to effectively radiate heat, it can't just face the surface of a table because that will just heat the table up to the same temperature and then you don't radiate much more heat.
For optimal performance you need to either place the machine in a stand or flip it over on the table so that the bottom panel is facing preferably a cool area of the room (not under the sun beside a window).

Results

All tests are done in clamshell mode, this makes a difference because the CPU package actually draws about 5W more power regardless of everything else, when you output video.
Picture1.png

In this chart blue represents stock obviously, I tested by simply opening up a save game in StarCraft 2 in Windows with turbo boost disabled, which produces a constant and reproducible load.

Orange is the moded machine but just placed on the table like normal. As you can see there is an improvement but not much.

The magic happens when you flip the machine over and let it just radiate into the room, represented by the gray line. The yellow line represents the flipped over machine with a big aluminum heat sink just placed on it. There is almost no difference from the heat sink because heat sinks don't provide significantly increased surface area for radiation, it gives improved surface area for convection.

I have not tested this but placing it on a laptop cooler should be just as effective as flipping it over on the table. (where as those products don't actually help the stock laptop, or most other laptops for that matter)

If I add a fan to blow across the heat sink, temperatures are further reduced to around 72 degrees. Such a setup can completely eliminate internal fan activity even under heavy loads. And you can use fan control to force the fans to minimum speed and still run at over 30w without hitting 100 degrees for any amount of time.
DSC00969.jpg

Picture2.png


I also tested constant power, by immediately running Cinebench after I warm up the machine with StarCraft. As you can see, the stock machine can then only accommodate about 25w of cpu power, while the moded machine can run at 31W.

At this point CPU power is basically bottlenecked by thermal paste performance, even with ice packs directly on the bottom panel, I could not really get any high power through the CPU. I'm guessing I would need to apply liquid metal for further improvements. Interestingly, when you distribute the load across CPU and GPU, you can get like 40w through the package without thermal throttling but the CPU can only take about 35.

Potential problems

Obviously this makes the bottom cover dangerously hot! You think your Touch Bar is hot? that won't actually burn you, not for like 10 minutes. This mod makes the bottom cover so hot it can burn you in a few seconds! Unless of course you have just removed your external cooling equipment.

This means you can no longer game with the thing on your lap without a blanket, which I don't think is an important use case to consider. You can still browser the web or watch videos with it on your lap no problem. In fact you can cool the laptop with your blood and circulatory system this way, so long as the thermal power doesn't overwhelm your skin.

So I wouldn't place the $200 leather sleeve under my MacBook after the mod if I plan to run heavy tasks, but regular cloth, fabrics and wood surfaces should be fine with such temperatures, which is as high as you can expect from a hot cup of coffee.
 
Last edited:

1096bimu

macrumors 6502
Original poster
Nov 7, 2017
319
291
It’s just not worth it for a portable if you need more performance then just buy a desktop and be done with it.
Because I already have a desktop?
And what makes you think it is more performance I am after?
 

1096bimu

macrumors 6502
Original poster
Nov 7, 2017
319
291
Because if you don’t need more performance and your mod makes it too hot to use as a standard notebook (as noted by yourself) then it is an utterly futile excercise.
It doesn't, try actually reading the post.

You can still browser the web or watch videos with it on your lap no problem.
[doublepost=1539279064][/doublepost]
So I have to use the laptop in clamshell mode upside down? I agree with @Samuelsan2001, its a futile exercise. I got a laptop so I could use it on the go
Why do people keep replying without actually reading the post?
placing it on a laptop cooler should be just as effective as flipping it over on the table.
 

1096bimu

macrumors 6502
Original poster
Nov 7, 2017
319
291
LOL, what ever you say :rolleyes:

The point remains its a futile exercise
except it isn't, even just used normally you get a 10 degrees improvement and reduced power consumption.
Again, you didn't read it, which would've been fine if you didn't also speak nonsense based on your ignorance.
 
  • Like
Reactions: me55

Samuelsan2001

macrumors 604
Oct 24, 2013
7,694
2,121
except it isn't, even just used normally you get a 10 degrees improvement and reduced power consumption.
Again, you didn't read it, which would've been fine if you didn't also speak nonsense based on your ignorance.
You specifically state that you have to use it upside down in clamshell to get any direct benefit from it performance wise. in which case you might as well just use your desktop. That is the reason I stated it was futile excercise.

You then go on to suggest that the surface being dangerously hotter (this term is used more than once In your original post even under the pros and cons section) is a good thing and that your circulatory system acts as a heat sink, this is utter nonsense. If it’s getting hot enough that your blood is making a difference you are risking damage to your skin, and causing damage to any surface you use it on for any length of time.

There is reason laptops use air to keep the base of themselves relatively cool, and you’ve just blocked that airflow with your thermal paste.
Notebooks are carefully balanced to provide the performance that they can within the restraints of a usable portable device, your mod ignores all of those excellent decisions for no seemingly advantageous outcome. I couldn’t care less if my cpu is ten degrees cooler if it means I can’t use it as a use anywhere laptop whenever I like.
 

maflynn

Moderator
Staff member
May 3, 2009
66,686
33,574
Boston
except it isn't, even just used normally you get a 10 degrees improvement and reduced power consumption.
Again, you didn't read it, which would've been fine if you didn't also speak nonsense based on your ignorance.
Ignorance, nah, just using your own images and words to indicate the ludicouse nature. I mean why do a mod that can burn you in a few seconds (your words as noted below).
This mod makes the bottom cover so hot it can burn you in a few seconds!
So if you want accuse me of nonsense, go ahead, but at least I'm not suggesting to use my circulatory system to cool a laptop
In fact you can cool the laptop with your blood and circulatory system
 

leman

macrumors G4
Oct 14, 2008
10,744
5,243
Could you post some before/after performance tests? How much improvement do you see?
 

ilikewhey

macrumors 68000
May 14, 2014
1,521
1,634
nyc upper east
oh man that is a dope mod, and its reversible not permanent, my mac pro just took a dump so i ordered a mantiz venus and planning to transform my 15inch mbp into a desktop station, my only worry was the cpu would kick the fan into overdrive, i have a noctua d14 and a cryorig r1 sitting, does it have to be a huge block of aluminum or can i use a noctua d14 and place it right ontop of the thermal pad treatment area.

btw can you post link of the thermal pad? i wanna order some when my mantiz arrives
 

1096bimu

macrumors 6502
Original poster
Nov 7, 2017
319
291
You specifically state that you have to use it upside down in clamshell to get any direct benefit from it performance wise. in which case you might as well just use your desktop. That is the reason I stated it was futile excercise.

You then go on to suggest that the surface being dangerously hotter (this term is used more than once In your original post even under the pros and cons section) is a good thing and that your circulatory system acts as a heat sink, this is utter nonsense. If it’s getting hot enough that your blood is making a difference you are risking damage to your skin, and causing damage to any surface you use it on for any length of time.

There is reason laptops use air to keep the base of themselves relatively cool, and you’ve just blocked that airflow with your thermal paste.
Notebooks are carefully balanced to provide the performance that they can within the restraints of a usable portable device, your mod ignores all of those excellent decisions for no seemingly advantageous outcome. I couldn’t care less if my cpu is ten degrees cooler if it means I can’t use it as a use anywhere laptop whenever I like.
Well then it would seem that what you lack isn't reading of this post, it's science.

Whether or not it gets dangerously hot depends on what you are doing and how long you have been doing it for. There is no risk if you just place it on your lap and browse the web.

The thermal pads aren't blocking any airflow if you know where the flow is going, which apparently you do not. But I can tell you that they aren't blocking anything and there is no reduction in cooling performance in any configuration.

So why don't you stop talking about things you apparently are ignorant about?
[doublepost=1539312776][/doublepost]
Ignorance, nah, just using your own images and words to indicate the ludicouse nature. I mean why do a mod that can burn you in a few seconds (your words as noted below).

So if you want accuse me of nonsense, go ahead, but at least I'm not suggesting to use my circulatory system to cool a laptop
You can also crush your finger if you stick it between the hinge and open the laptop. Of course there will always be ways to hurt yourself if you are stupid.

There is nothing non-sensical about cooling the laptop with your skin, that is called the fallacy of appealing to ridicule, most likely because you don't understand the science.
[doublepost=1539313384][/doublepost]
oh man that is a dope mod, and its reversible not permanent, my mac pro just took a dump so i ordered a mantiz venus and planning to transform my 15inch mbp into a desktop station, my only worry was the cpu would kick the fan into overdrive, i have a noctua d14 and a cryorig r1 sitting, does it have to be a huge block of aluminum or can i use a noctua d14 and place it right ontop of the thermal pad treatment area.

btw can you post link of the thermal pad? i wanna order some when my mantiz arrives
Yes that is exactly what you can do although it probably won't be as effective, since the regular CPU cooler has a small cold plate at the bottom, which in this case is problematic because that isn't in direct contact with the CPU.
You may also want to first open up the machine to check the exact clearance of your model between the heat pipe and the bottom cover first and order the appropriate thermal pad.

You want to order the best thermal pad you can find, pay attention to their heat conductivity, most are around 3-6w/k/m I found one that is 12w/k/m made by Gelid.
 

ilikewhey

macrumors 68000
May 14, 2014
1,521
1,634
nyc upper east
do you have a link to the heatsink block, no cpu or gpu cooler i know have that big of a cold plate for contact, i'm gonna see how bad it is in clamshell mode when i get my mantiz venus first, but this type of mod have been on my mind for awhile, ur the first that actually executed.
 

1096bimu

macrumors 6502
Original poster
Nov 7, 2017
319
291
Could you post some before/after performance tests? How much improvement do you see?
As I have posted, you get higher sustained clock speeds, and performance is directly related to clock speed. The clock speed is 18% higher by the way.
[doublepost=1539314237][/doublepost]
do you have a link to the heatsink block, no cpu or gpu cooler i know have that big of a cold plate for contact, i'm gonna see how bad it is in clamshell mode when i get my mantiz venus first, but this type of mod have been on my mind for awhile, ur the first that actually executed.
I'm traveling in China, so you can't use the links I used to buy it. It's just a cheap heat sink for industrial use, I got it for about $5 shipping included. I mean there isn't that much of a difference with or without the external heat sink in terms of thermals. If you really want one try looking through eBay or AliExpress for industrial heat sinks.
 

ilikewhey

macrumors 68000
May 14, 2014
1,521
1,634
nyc upper east
shoot alright i guess my noctua d14 would do for now. btw is it necessary to place pads on the heatsink too? or is the pads directly on gpu/cpu block enough
 

avolmar

macrumors newbie
Sep 19, 2018
12
0
I think it’s a cool idea (thanks for sharing your experiences). Since I quite often have to heavy workload use (export hundreds of photography from Lightroom) I see there is much more improvement possibilities regarding clock speed. So I am seriously thinking to use that solution.
 

1096bimu

macrumors 6502
Original poster
Nov 7, 2017
319
291
shoot alright i guess my noctua d14 would do for now. btw is it necessary to place pads on the heatsink too? or is the pads directly on gpu/cpu block enough
I tried a pad under the heat sink, I don't think it makes much of a difference. Contact is probably better with a pad but then the pad itself isn't as conductive as bare metal so those factors probably just cancel out. Definitely don't use a pad with a CPU cooler because the cold plate is so small that the thermal conductivity of thermal pads will be a big bottle neck over such a small surface area.
 

ApfelKuchen

macrumors 68040
Aug 28, 2012
3,581
2,223
Between the coasts
How about a "Stock Up" test? The Mod Down results in just a 6 degree reduction over Stock (Down), yet Mod Up is good for 11 degrees more than Mod Down. If it were to turn out that Stock Up also resulted in an 11 degree improvement over Stock (Down), then all that modding would turn out to be less important than the orientation of the stock device. And that kludgy heat sink makes the least difference of all.

In other words, why risk the warranty and invest all that time and money, when all one might have to do is flip the clamshell so it's belly up?
 

Thysanoptera

macrumors 6502a
Jun 12, 2018
795
766
Pittsburgh, PA
First of all you have a really bad sample of i9, my 2.2 does 3.3 GHz under Cinebench. What’s your score without the mod? Low 900’s? There should be no issues dissipating 35W CPU package with stock cooling. It kind of looks like some other reported bad samples. Investigate how flat the CPU heatsink plate is and replace TIM, you’d probably get the same results without giant block of aluminum attached to the bottom.

If the experience with XPS15 relates to this chassis in any way, the most worthwhile mod for it was to put thermal pads on voltage regulators, but for that it was actually best to use low conductivity pads, the high conductivity ones didn’t reduce throttling any more but significantly increased surface temperature.
 
  • Like
Reactions: elamor4738
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.