M2 MacBook Air Teardown: Apple Forgot the Heatsink? | Hacker News Reader

M2 MacBook Air Teardown: Apple Forgot the Heatsink?

ifixit.com

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Here's a review of a Lenovo's new thin and light Thinkpad X1 Yoga with Intel's current gen flagship laptop CPU:

>Unfortunately, the laptop got uncomfortably hot in its Best performance mode during testing, even with light workloads.

https://arstechnica.com/gadgets/2022/07/review-lenovos-think...

This is a laptop with two fans that cannot be used comfortably, even for light workloads, without being set to throttle all the time.

A fanless laptop that throttles under sustained load is perfectly normal. A laptop with active cooling that is too hot for light use until you configure it to always throttle is not.

In the case of the Intel i7-1280P in the Lenovo, it's not entirely surprising that it heats up. Under Tau it can draw 64W if allowed to, per Intel ARK.

That's on par with a mid-range AMD desktop CPU -- a Ryzen 5600X pulls 67.2W flat out.

Apple's M1 Max capped at about 39.7W, and the M1 Pro was around 33.6W. So the M2 getting hot isn't surprising since it's likely in the 25-30W range. I agree that 25+ watts is a lot of heat to dissipate given the design of its thermal solution.

I have the previous version (gen 6) and I can confirm the heat problems. You can not watch a 4k movie and charge it at the same time. Soon after you plug in the charging cable the upper left corner of the computer will be so hot that you (almost) can burn yourself. When that happen the computer will slow down to the point where it is not really usable.

At this point you can turn the computer upside down to allow the back side of the computer to cool down (get some air). After a few minutes it has cooled down sufficient to that you can continue using the computer and charge it at the same time, but shortly after you will have to repeat this.

If think the backside of metal case get so hot that not enough hot air cannot escape. If you can place the computer in any position that allows air to flow over the back side of the case everything works, but placed on a table or similar you have severe thermal issues if you charge it at the same time at the same time you do anything mildly CPU intensive.

Perhaps may not be as big of a problem given how efficient the chip is and also the fact that the latest iPhones have huge computational power all with passive cooling. Also, iirc aliminium chassis acts as a heatsink.

If you look at some basic tests you can see it quickly heats up to about 105 degrees Celsius. And leading to degraded performance. And that is without even touching the GPU. I honestly was really excited about the M series. But it seems Apple is going down the exact some route they did with Intel. Massively underperforming in the thermal department. I pray this is an outlier. Or at the very least the pro series will not have this problem again.

Yeah seems that way. It sucks because I was seriously considering this machine, but it looks like Apple made this machine to just push more people towards their Pro line up.

Apple made this machine for those who want a laptop that doesn’t need sustained heavy workloads, I.e. most people in the general population.

Yeah that's me lol, my 2015 tbMBP is only used for watching movies and replying to emails. For everything else there is a desktop

>most people in the general population.

And we have a winner!

It's quite surprising (well actually it's not) what there are many people who thinks what Apple does things for their use case, which is usually something like recompiling Chrome or something.

By all means list the 5+ minute long sustained workloads that ordinary people are running on their laptops.

The only use cases for which the MBA is not sustainable are Pro ones e.g. 3D rendering, CFDs etc so it's hard to see how Apple is being unreasonable here.

> The only use cases for which the MBA is not sustainable are Pro ones e.g. 3D rendering, CFDs etc so it's hard to see how Apple is being unreasonable here.

It's not about Apple being unreasonable. It's just that what you call "Pro use cases" could reasonably be done with the Air if it had slightly better thermal management in the same way an iPad Pro running macOs could replace a current MacBook Air. Apple likes to use these design decisions to segment its markets.

Yes, that's the point. The Air is targeted at the people who don't need to do those things and would rather the laptop be smaller and lighter.

A MacBook Air with better thermal management is an entry level MacBook Pro.

No, that's not the point. The Air is intentionally gimped by inefficient thermal management so people who want better performance have to buy a Pro. Apple could make the Air performs close to the entry level MacBook Pro but doesn't because that's how they segment. They have been quite good at introducing products which can compete on price while protecting their higher margin sales.

It's a very common practice for Apple. In the same way their laptop and tablet offerings have been converging for years from a technical point of view but they intentionally limit what the tablet can do so has to not cannibalise their laptop sales.

If you prioritize sustained load performance, then the pro machines are designed for that.

If you have less need for that or don't care about a mild slowdown on the rare occasions where you can push it into throttle territory, then the Air would be good for you. I would gladly trade away some maximum performance in order to get a cheaper, lighter machine that doesn't need a fan blowing.

This is not about "gimping" the Air. it is about tailoring the balance of features, performance, and cost to meet the needs of different segments of customers.

> This is not about "gimping" the Air. it is about tailoring the balance of features, performance, and cost to meet the needs of different segments of customers.

Yes but it’s pretty obvious when you look at the design that Apple is intentionally limiting the performance of its cheaper products so as to not hurt the Pro line too much.

The 13 MBP with M2 is almost the same price as the M2 MBA. The MBP is a little more performance when running continuous heavy processing due to its fan. The MBP is also thicker, heavier and has a fan running. The MBA runs almost as fast but is lighter and never has a fan.

If you look at the Six Colors review, they show some throttling at 10 minutes on a Cinebench test. The MBP with a fan scored 8638 and the MBA without scored 8211. That kind of difference is not worth adding a fan or putting in some heat pads that make the case get hotter. It just means that the most portable Mac is ever so slightly slower than the low end Pro Mac. I'm happy with that. https://i0.wp.com/sixcolors.com/wp-content/uploads/2022/07/t...

https://sixcolors.com/post/2022/07/m2-macbook-air-review-a-n...

I disagree. It's not "inefficient" since the laptop is not meant for sustained heavy loads. That's a trade-off, not a gimp.

Want heavy loads, get the thicker and heavier one with active cooling. Don't care about heavy loads, great have this one that is skinnier and lighter.

Once again you are ignoring my point. The Air could be better without active cooling. The passive cooling solution in place is intentionally poorer that it could be so as to limit the performance. That’s fairly standard for Apple. It doesn’t mean that the Air is a bad laptop just that it’s purposefully held back by Apple design choice.

I know Apple sells a model tailored to heavier load. The point of limiting the performance of the Air is to not cannibalise its sell numbers too much.

I’m not entirely convinced that they could have done so without another trade off. Yes they could have made the heat transfer from the cpu/gpu to the chassis better. So it could make better use of that bottom plate to dissipate heat.

But the cost of that would have been a laptop that is warmer/hotter to the touch. Idk how much hotter it would be, but I’m sure there’ll be a YouTuber or two who will test it out and less us know. Maybe it’s only 1-2C, maybe it’s 15-20. It’d accept 1-2C, but I would not accept 15-20.

Games?

Gaming is pretty ordinary. And since you can run apps on the M2 you have a choice with a LOT of games. You can even run windows games using with Rosetta 2.

It’s not really a efficient heat sink since it’s just a big slab with no fins to actually cool itself down. Now it’ll heat up the whole chassis and then stay hot. It also doesn’t look like the metal piece on top of the CPU is seriously connected to the chassis (like with direct contact and thermal paste)

No, a small finned heat sink with no air movement would be worse. They are spreading out the heat to move it out via a large surface area of the metal case. I'm guessing the paste wouldn't help much since the heat flow density is fairly low. Think of it this way, the thermal resistance per sq mm is relatively high, but the total parallel thermal resistance is still very low because of the large area.

Don't forget, this machine is focused on the consumer mass market, not the high performance market. It will never break a sweat for the vast majority of typical use cases. Even when throttling a little bit, it still vastly outperforms the Intel MB Air it replaces.

Get a 14" MB Pro if you really want incredible thermal performance.

> It also doesn’t look like the metal piece on top of the CPU is seriously connected to the chassis

It's not supposed to be connected.

You are describing the hack that some people do where they add a thermal bridge between the two. Yes you get better performance but at the cost of serious injuries due to the significantly increased heat being directed to your lap.

Apple has said that they explicitly are not using the chassis to cool the chips as that would transfer too much heat to the human operator. They didn't "forget the heatsink". This MBA was design for tasks and usage that most of us do that do not involve simultaneous FCP renders of 8K video and 3D rendering. If you are doing that, you might want to look at the MB Pro. The rest of us don't need to worry about it.

Weird. I have a 2 year old MBP that gets turns it's fans on when I open slack and intellij at the same time.

Yes, that will happen with any of the Intel MBPs. That was one of the best benefits of moving to Apple Silicon SOCs. It takes a lot more load to get them hot.

Seems accurate. My understanding is the Pro versions always come with a better cooling solution than Air

Someone could make a replacement bottom with fans, heatsink, replacement speakers, thermal paste, etc.

Or just buy the 13 inch M2 MacBook Pro or previous M1 version.

At least then you won't void your warranty.

The M2 MBP has terrible heat management issues also.

but is it really "terrible"? From the videos that I saw, once you got past the headline and saw the result, yet, if you pushed really heavy loads it would start throttling. when that happened, it would slow down. in most cases that slowing was not unusable. Unless you plan to do a lot of that kind of process, then it should not be a problem, If you do a lot of that, then you would want the real pro machines, the 14/16" MBPs. That 13" is still a placeholder with the old chassis and old cooling system and is only "pro" in the broadest of definitions.

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