Does the metal back of an iphone work as a heatsink?

[zaza]

Or do Apple just use metal cause it looks better?
I'm wondering if the reason iphone CPU and GPU throttle much less than android phones (esp. the cheap plastic Samsung phones) is cause the aluminum back is in contact with the chip and thus dissipates its heat, or because Apple chips are just more thermally efficient than others?
If the metal back really was in contact with the chip then wouldn't simply touching it with your hand cause an electrostatic discharge that would fry the chip?

 

[mnewsham]

esp. the cheap plastic Samsung phones

Current Samsung phones have an aluminium chassis... they also run cooler than other android flagships right now (Z5, 6P, V10, etc) Glad to see you dont have an agenda though.


Seriously though, of course metal acts as a heatsink, that's pretty obvious.


It might not be significant depending on how it was designed, but it will still help dissipate heat faster just because the chassis is metal.

 

[lxskllr]

Metal phones suck. (good)Plastic is the ideal material, and when it comes time to get a new phone, I will look for plastic, and hope they still exist.

 

[Oyeve]

Current Samsung phones have an aluminium chassis... they also run cooler than other android flagships right now (Z5, 6P, V10, etc) Glad to see you dont have an agenda though.


Seriously though, of course metal acts as a heatsink, that's pretty obvious.


It might not be significant depending on how it was designed, but it will still help dissipate heat faster just because the chassis is metal.

I disagree for the V10. I use mine all the time for video watch and gaming and it barely get very warm. My Note 4 on the other hand, would feel like it was gonna melt, especially if I used the Gear VR with it.

 

[zaza]

Current Samsung phones have an aluminium chassis... they also run cooler than other android flagships right now (Z5, 6P, V10, etc) Glad to see you dont have an agenda though.


Seriously though, of course metal acts as a heatsink, that's pretty obvious.


It might not be significant depending on how it was designed, but it will still help dissipate heat faster just because the chassis is metal.

If it's a heatsink then were the hell is the thermal paste?
As anyone who has worked with heatsinks will tell you, if there's even the tinest amount of air between the heatsink and the chip then the heatsink will not dissipate any heat at all, because air has virtually zero thermal conductivity.

 

[mnewsham]

I disagree for the V10.

V10 uses SD808 which is just an SD810 without the extra 2 A57 cores. It thermal throttles just like the SD810 does, LG just happens to use some decent throttling so it isn't too noticeable and it never gets overly hot. But this reflects in benchmarks, especially if you run them back to back and let the SD808 get a bit warm from successive runs.

Also, the Note4 uses SD805 or Exynos 5433, both of which are older than the current samsung line using the Exynos 7420 which runs cooler simply because it has the luxury of being built on a 14nm process, not 20nm (or 28nm in the case of SD805) like the others.

 

[Artdeco]

The Al case also dissipates the heat from the battery.

 

[dawheat]

Doesn't seem like it - the A9 SOC is on top of the logic board facing the display and the back of the board has other chips. The back of the board does seem to touch the back shell.

 

[JeffMD]

I haven't seen any phones in any teardown videos that I can recall where the processor/motherboard had any kind of connection (like paste) to the back case as an effort to use it as a heatsink. The CPU usually has a metal cage around it which is probably acting as its heatsink, but otherwise its only form of heat dissipation is through the motherboard.

 

[zaza]

I haven't seen any phones in any teardown videos that I can recall where the processor/motherboard had any kind of connection (like paste) to the back case as an effort to use it as a heatsink. The CPU usually has a metal cage around it which is probably acting as its heatsink, but otherwise its only form of heat dissipation is through the motherboard.

That's right.
I've seen iphone teardown videos and never saw any thermal paste.
What's annoying is some review sites that claim that metal phones are more thermally efficient cause the back dissipates the heat.

 

[lxskllr]

What's annoying is some review sites that claim that metal phones are more thermally efficient cause the back dissipates the heat.

That's not incorrect. A metal phone should dissipate more heat regardless of direct contact with electronics. Whether or not it makes a significant difference I don't know, but it should be a measurable difference.

 

[JeffMD]

ixs, the heat still has to dissipate through a plastic motherboard. We also don't know how much of that back heat is from direct contact or simply transferred through the air.

The fact that these chips only true heatsink is the metal enclosure tells me that these chips don't emit to much heat quickly. The battery and screen are probably producing the same amount of heat even.

 

[biostud]

Metal phones suck. (good)Plastic is the ideal material, and when it comes time to get a new phone, I will look for plastic, and hope they still exist.

Windows phones

 

[Zodiark1593]

Aluminum is useful for performance-aimed phones as the material can, in fact, act as a heatsink. However, I don't see much in the way of assuring proper contact between the chip and the aluminum, at least, not nearly the same amount of care as one would take on a pc chip.

If the aluminum was critical in heat dissipation, we'd probably see bare dies mated directly to the aluminum surface via thermal grease. Seeing as we don't, you're probably losing relatively little performance in a decent plastic vs aluminum exterior.

 

[JeffMD]

zodi, my guess is having something that can put pressure on the chip in such a direct way would lead to cracked die's with a single drop.

 

[zaza]

zodi, my guess is having something that can put pressure on the chip in such a direct way would lead to cracked die's with a single drop.

That's not the reason.
The reason you can't have the metal back in contact with the chip is because if you did then you could send an Electrostatic discharge to the chip by just touching the back and as a result you'd destroy the chip.
Electrostatic discharge is the reason you're advised to ground yourself whenever you're opening an electronic device.