HACKER Q&A
📣 briefcomment

Will devices keep getting hotter, uncomfortably so?


It seems like newer, faster, and more powerful devices also run hotter. I've noticed it with my 2020 MBP, which gets too hot to type with while playing a relatively simple game, and which seems to be hotter than my 2013 Air playing the same game. My friend's iPhone X seems to get hotter than my iPhone 6, which in turn seems to get hotter than my older phones. There are a lot of comments on how most of the volume of the PS5 is there to account for heat dissipation.

As devices improve, is it just expected that they'll create more heat?


  👤 ksaj Accepted Answer ✓
I think the irony is that the "entry level" devices tend to be plenty fast and capable, yet produce nowhere near the level of heat.

For example, I think the LG K31 is an amazing phone. It's fast, it has plenty of memory, and it has really good cameras. It charges fast, stays charged long, and doesn't get hot.

ARM is also in the business of making chips that don't get as hot as many of its competitors.

I remember when that was AMD's domain. Now I guess it is ARM's time to shine.


👤 KiranRao0
While this appears true when looking at a single device class, I could argue that it's not true when looking at computing in general.

The current iPhone X consumes more power than an iPhone 6. However, my dominant 2020 computer (phone) consumes less power than my dominant 2010 computer (laptop) which consumes less power than my 2000 computer (desktop).


👤 muzani
My wife's Mi phone used to overheat with games, but the new ones do much better. Samsung is doing better too.

On the other hand, the iPhones are doing much worse, overheating simply by putting it in your pocket, on the bed, or streaming a video with mobile data on YouTube.


👤 Someone
Same game, but also same FPS, resolution, visual effects, and screen brightness? That would surprise me.

For reference, the 2013 MacBook Air has 1440 × 900 ≈ 1,3M pixels, the 2020 MacBook Pro 2560 × 1600 ≈ 4M. That’s almost three times as much. Screen brightness is 300 vs 500 nits.


👤 ArtWomb
Nanoscale energy harvesting is a reality in the lab. Why hasn't it been deployed at scale to power microelectronic devices?

👤 sloaken
Your display is the primary drain on battery, as such it is likely the primary cause of heat.

👤 eyelidlessness
It depends on a few factors, primarily determined by choices made by the device maker, informed by the available technologies and their market targets.

I can’t speak to these later model iPhones (I’m typing this on an 8 Plus; for what it’s worth, I’ve found this one to be consistently cooler than my 6 before it, and my 5 before that; I was a luddite with a land line before that so I have no more anecdata), but generally speaking while iPhones can and do get warm, their thermals are incredibly impressive given the form factor. These are devices with passive cooling which are performance competitive with the MBP you mention, despite the engineering that went into its own active cooling system.

These devices make different tradeoffs, for different goals. But also importantly, they use different technologies. And with these specific devices in mind, that’s where “it depends” gets very speculative but also interesting at this moment.

I think it’s pretty likely that passively cooled handheld devices will continue to be designed by facing tough choices between performance and efficiency (heat budget, yes, but also power drain). Of course those tough choices, combined with growing expectations of what a handheld can do, are what have driven the impressive improvements in performance per efficiency in the iPhone line.

And Macs are about to transition to the same CPU/GPU platform. So “it depends” is really about to what degree Apple will use the performance per efficiency gains in that switch to prioritize:

- Performance overall

- Thermals and power consumption

- Form factor

And at this point the rumor mill is surprisingly quiet! It’s hard to say what balance they’ll strike, in which Mac products.

Speculating based on many years of being an Apple customer (as in I’m an Apple greybeard, I’ve had in my home or owned at least one Apple device for each major ISA they’ve shipped since the original Mac)... I think they’ll probably target all of the categories, but favor (in order of priority, highest to lowest):

- Form factor “improvements”: taking advantage of better thermals to make devices thinner/lighter/smaller/more visually striking

- Form factor improvements that are not controversial enough to warrant scare quotes or debate about whether it’s a genuine improvement: improved battery life, improved cooling (and they’ll probably focus at least the marketing on noise reduction)

- At least enough of a performance advantage to show (some cherry picked set of) CPU/GPU bound apps outperforming the same apps compiled for x64 on the previous gen Mac, and (also cherry picked) x64 apps performing competitively under emulation

In other words, I expect Apple to keep the same set of priorities they’ve had, for better and worse, since the PowerPC switch, replicated in the colorful plastic era, the Cube, the mini, the Intel switch, the introduction of the iPhone, the retina MBP, the trash tube.

tl;dr they’re probably gonna make some modest heat dissipation improvements, but prioritize other things higher, because they’ve very seldom deviated from that since the Pepsi guy left.

Edit: I honestly don’t remember my Apple lore well enough to remember if it was the Pepsi guy! I remember the product direction pretty well, but the human trivia isn’t my thing.


👤 7786655
s/devices/Apple devices/?

👤 jdbernard
Apple tends to sacrifice thermals for thinness.