MacBook Air 2015 13in. Heatsink/CPU Chipset Question

[haine84]

I have an 2015 MacBook Air 13 inch (A1466) and I decided to put new thermal paste on my heatsink and CPU. Since I have owned this computer for three years. So I disassembled the computer and I was shocked at the lack of amount of paste and decent coverage of the original paste from Apple. I have posted some pictures that I took and the first one is when I took the heatsink off. The second picture is of my redo job. Yes I did clean it up before I put it on so only thermal paste would be where it needed to be.

I am assuming the larger chip is the CPU naturally.
So, my question is what is the smaller chip that is covered by the heatsink and I'm assuming needed paste but didn't have any. I've searched other threads and haven't found any technical question like this covered. I haven't been able to find any information on google either, at least none that helpful.

I'm grateful for any enlightenment on this any one can give.

Thank you,

Justin

 

[Earl Urley]

That's the GPU, in this case an Intel HD 6000. Seem to remember that Apple recommends you don't put paste on it but that is ******** in my opinion as in my experience it gets just as hot if not more than the CPU, depending on what your app is doing with graphics.

I always put a smidge on the GPU on my 2010 MBA..

 

[JPack]

1. The smaller chip is the PCH (south bridge), not GPU.

2. The PCH runs at a much lower temperature than the CPU. The PCH should not be covered with thermal paste. Otherwise, heat will spread from the CPU to the PCH.

3. If you look carefully, the heatsink does not make contact with the PCH. This is by design. The PCH relies on convection cooling. If you apply thermal paste in an attempt to fill the gap, the thermal resistance will be high and the heat from the CPU will transfer over.

 

[haine84]

Thanks you for your responses.

I did find a website called ifixit.com and they list it as both the CPU and GPU (attached picture). I also was able to find a picture (2nd Picture) of the GPU chipset (which you are right Earl, Intel HD 6000) after taking a break last night and it matches pretty well with my picture.

Either way, I did notice JPack there was a small recess to the side of the heatsink where the smaller chip sits and thought it was odd. And I could see how heat transfer could be an issue. It just seems kinda dumb to have the heatsink cover both if they didn't want thermal paste to be applied on there. I would think that small gap would make it harder to passively cool than just leaving it uncovered. I also didn't think the south bridge would be that close to the CPU since the CPU is usually tied to the north bridge.

If you buy video cards with fans on them I'm sure they have thermal paste. And, even some of the older video cards even had plastic heatsinks that were passively cooled. I'm sure they had some sort of thermal paste on them as well. Even the south bridge usually has some sort of heatsink as well that is passively cooled on modern mother boards don't they. The ASUS board I used to build my older desktop (10 years ago) had copper heatsinks on both the south and north bridges.

Seems weird to me, but, with Apple I am beginning to see that the most logical choices aren't the ones always made. My point being an 2020 MacBook Air with an i7 Quad core with what seems to be a passively cooled plastic heatsink.

But it does seem a little bit more snappy, the fans aren't winding up as much and I haven't been getting a lot of the video lag from just moving my cursor across the screen since I redid it. I don't really use this computer for anything heavy anyway. I plan on resetting this computer in the next week or so since I haven't done it in about two years. But I digress, if I notice it acting funny I will redo it.


Thank you both for your inputs it was very helpful and made me think about it a little more.

Justin

I'll update in week or so if I decided to do it or not just incase anyone else has this issue.

 

[JPack]

iFixit doesn't say the smaller die is the GPU. They're simply saying the package is the CPU and GPU.

There's no ambiguity here. The smaller chip is not the GPU. It's the PCH.



[automerge]1591563320[/automerge]

Either way, I did notice JPack there was a small recess to the side of the heatsink where the smaller chip sits and thought it was odd. And I could see how heat transfer could be an issue. It just seems kinda dumb to have the heatsink cover both if they didn't want thermal paste to be applied on there. I would think that small gap would make it harder to passively cool than just leaving it uncovered. I also didn't think the south bridge would be that close to the CPU since the CPU is usually tied to the north bridge.

If you buy video cards with fans on them I'm sure they have thermal paste. And, even some of the older video cards even had plastic heatsinks that were passively cooled. I'm sure they had some sort of thermal paste on them as well. Even the south bridge usually has some sort of heatsink as well that is passively cooled on modern mother boards don't they. The ASUS board I used to build my older desktop (10 years ago) had copper heatsinks on both the south and north bridges.

The issue here is - the CPU/GPU is 15W and the PCH is 3W. If the two were connected by a single heatsink, 15W would spill over to the PCH. At 3W, the PCH doesn't need a heatsink.

 

[haine84]

iFixit doesn't say the smaller die is the GPU. They're simply saying the package is the CPU and GPU.

There's no ambiguity here. The smaller chip is not the GPU. It's the PCH.

View attachment 922336
View attachment 922337
[automerge]1591563320[/automerge]


The issue here is - the CPU/GPU is 15W and the PCH is 3W. If the two were connected by a single heatsink, 15W would spill over to the PCH. At 3W, the PCH doesn't need a heatsink.

Ok, yeah I like those pictures better. That Core Map is awesome and would of been handy to have to begin with. That makes sense because I was thinking it was odd that there would be an extra chip if the graphics were suppose to be integrated. Thats what is so irritating about this stuff is that one can hardly find what they need to know in a timely manner and why these forums are so crucial to consumers.

Thank you JPack for posting those pictures. I guess I will be opening it back up after all and redoing it.