MBP 16" runs hot, but low temp?

[zshane1125]

Hey guys, I own both a MBP 2018 15" and a MBP 2019 16", they run around the same temperature with the same apps and loads.

but the bottom of the 16" runs really warm, like almost 70-80C, but the temp sensor tells me 45-55C
the 15" is displaying the same temp 45-55C, but the bottom is much much cooler to touch, actually feels like 45-55C.

both temp sensors are CPU core 1

The only difference is that on the 15" I have a dbrand skin, but that should not make that much of a difference right, at least in the past I felt no difference with or without dbrand skin, heat feels aligned with the displayed temperature.

What's going on here? the new MBP 16" is 2 days old.

Thanks.

 

[mikethebigo]

Hey guys, I own both a MBP 2018 15" and a MBP 2019 16", they run around the same temperature with the same apps and loads.

but the bottom of the 16" runs really warm, like almost 70-80C, but the temp sensor tells me 45-55C
the 15" is displaying the same temp 45-55C, but the bottom is much much cooler to touch, actually feels like 45-55C.

both temp sensors are CPU core 1

The only difference is that on the 15" I have a dbrand skin, but that should not make that much of a difference right, at least in the past I felt no difference with or without dbrand skin, heat feels aligned with the displayed temperature.

What's going on here? the new MBP 16" is 2 days old.

Thanks.

Well the 16" has a different thermal system and a much larger heat pipe, perhaps it is diffusing more heat to the chassis.

 

[Howard2k]

Why not take off the skin and compare?

 

[mightyjabba]

If I had to guess I would say that it’s because the 16” is doing a better job of dispersing heat away from the core components. That’s part of what they mean by the improved thermals, which helps prevent the CPU from throttling itself to keep from burning itself up. Better that it be hot on the outside than on the inside, although I doubt there is actually a 30-degree difference between the CPU and the bottom of the computer.

 

[zshane1125]

Well the 16" has a different thermal system and a much larger heat pipe, perhaps it is diffusing more heat to the chassis.

Yes, that might be it, honestly, it runs really warm at the bottom compared to my older 2018 15"

Why not take off the skin and compare?

I ve had plenty of experience with my 15" without the dbrand skin, the bottom is much cooler.

If I had to guess I would say that it’s because the 16” is doing a better job of dispersing heat away from the core components. That’s part of what they mean by the improved thermals, which helps prevent the CPU from throttling itself to keep from burning itself up. Better that it be hot on the outside than on the inside, although I doubt there is actually a 30-degree difference between the CPU and the bottom of the computer.

Got it!

 

[leman]

but the bottom of the 16" runs really warm, like almost 70-80C, but the temp sensor tells me 45-55C
the 15" is displaying the same temp 45-55C, but the bottom is much much cooler to touch, actually feels like 45-55C.

80C would instantly give you quite severe burns and leave scorch marks on your furniture, so I am a bit skeptical here... how are you measuring it? According to notebookcheck tests, the external temperatures of the bottom case under load does not exceed 40C under load, making it one of the coolest laptops out there. Also, there is no way that the internal temperature is lower then the external one, just physically not possible. So again, how are you measuring your temperatures?

 

[matram]

From iStat menu, with a 20W system total power I get.

CPU Core 0: 60 C
GPU: 54 C
Air flow: 37 / 47 C
Palm rest: 35 / 33 C

The bottom casing feels warm to the touch, especially on the rights side, I would guess 40 - 45 C.

As already stated, surface temperature cannot exceed the highest temperature, which would most likely be the CPU.

This is a consequence of the second law of thermodynamics. If you are able to bypass that law, many people would be very interested as that would allow you to build a "perpetual motion machine".

 

[zshane1125]

Ok, let me rephrase it. Both MBPs have the same CPU temp readings, but the 16" bottom case is significantly hotter to touch, it's uncomfortable.

What I meant was:

the feel of the bottom case of the 16" when the CPU sensor is reading 45-55C is as hot as the bottom case of the 15" when the CPU sensor is reading 70-80C.

 

[leman]

the feel of the bottom case of the 16" when the CPU sensor is reading 45-55C is as hot as the bottom case of the 15" when the CPU sensor is reading 70-80C.

Ah, that makes more sense. Basically what you are saying is that the bottom chassis seems to have the same temperature no matter the temperature of the internals. Can't say that I find it surprising. When the laptop gets too hot, the fans will activate and blow the hot air from the back, but a certain amount of heat will be passively absorbed by the bottom chassis at all times. Again, looking at notebokcheck tests the difference in temperatures are just 25C on idle and 30C under load in certain regions of the bottom chassis.

To sum it up: if your machine operates as expected otherwise, I wouldn't worry about it at all. If it bothers you, then you already have an option of returning the machine, but I don't think that you laptop operates abnormally. At any rate you won't know that unless you take accurate temperature readings, for which you'd need an infrared thermometer.

 

[zshane1125]

Ah, that makes more sense. Basically what you are saying is that the bottom chassis seems to have the same temperature no matter the temperature of the internals. Can't say that I find it surprising. When the laptop gets too hot, the fans will activate and blow the hot air from the back, but a certain amount of heat will be passively absorbed by the bottom chassis at all times. Again, looking at notebokcheck tests the difference in temperatures are just 25C on idle and 30C under load in certain regions of the bottom chassis.

To sum it up: if your machine operates as expected otherwise, I wouldn't worry about it at all. If it bothers you, then you already have an option of returning the machine, but I don't think that you laptop operates abnormally. At any rate you won't know that unless you take accurate temperature readings, for which you'd need an infrared thermometer.

Noooo, I am saying the bottom case of the 16" is significantly hotter to touch than the bottom case of the 15" even though the CPU sensors on both computers are reading 45-55C.

Both are reading 45-55C, 16" bottom case is much hotter, making me uncomfortable. Which is very strange since both are reading 45-55....

 

[matram]

I would probably say this is to be expected.

In a very efficient cooling system the exhaust temperature from the fans will be close to the CPU core temperature, i.e. around 40 C in this case. This is not an issue, this is good thermal design.

As the chassis basically is part of "exhaust vent", the rear part of the chassis will reach a slightly lower temperature.

The fact that your 15" is cooler, basically indicates less efficient cooling where more of the temperature drop happens in the MBP before the air is expelled.

So I guess you need to decide which machine you prefer.

Both are reading 45-55C, 16" bottom case is much hotter, making me uncomfortable. Which is very strange since both are reading 45-55....