Macbook pro 13" - 2017 - heating issues when connected to external monitor

Question

My question is about chassis temperature and overheating issues. I have a recently bought a Macbook pro 13" - 2017 with two thunderbolt 3 ports. The notebook is performing fine, but when it is connected to the external Dell monitor (2560x1440 resolution), it gets uncomfortably hot. The same monitor was previously connected to a 2013 Macbook Air (i7) and there were no heating issue whatsoever (it would get hot only when doing extremely intesive CPU work).

The temperature on the left speaker is 40C (104F) and the temperature of the USB-C adapter's steel case is 45C (113F). The chassis around touchpad has 37C (99F). Measured with an IR thermometer. The room temperature is 26C (79F). The CPU usage is low (91% idle). The fan is near silent (iStats report that it is at 1950 RPMs.

The monitor is connected via USB-C - HDMI konverter.

When monitor is connected, the current draw is apx 50% higher than what it is when monitor is not connected (regular browsing). This was not measured scientifically, but through iStat Menus current draw information.

The adapter gets uncomfortably hot very quick and so does the chassis of the Macbook pro. It is even worse if the Macbook is charging at the same time (using the other available USB-C port). I previously owned Macbooks and a Macbook Air and none of them exhibited such heating issues.

I saw possible solutions on how to adjust the Energy Saver not to use the external graphics card, but it seems that this is not the case for this type of Macbooks -- at least, the settings are not present in the Energy Saver.

This is certainly unexpected from my side. Are such heating issues normal? Is there a way to limit GPU power usage or 'something'?

Answer 1

I just saw many people had the same issue as my self and first i didn't understand why. Now i do. The reason it gets so hot when hooked up to a monitor, even when you’re just running Word or Safari, is because the display outputs are hardwired to the dedicated GPU - if you’re using an external monitor, the dedicated GPU (graphic card) is in use regardless of how demanding the workload is. This puts more stress on the cooling system, resulting in higher-than-average temperatures ;) Thats the reason. I tried all my 6 Macbook Pro's and all does the same behavior. Switching to the dedicated graphic card and you can't just use the integrated iris.

Answer 2

With reference to Apple discussion:

1. The USB-C - HDMI converter I've been using was getting very hot. The heat was also transfering through the USB cable to the MacBook's body.
2. In addition to above, the Intel GPU is doing more work, so it is obviously getting warmer/hotter (you can see on the screenshot above, it is at 68 C).
3. In addition to that, the system controlled fan speed is too low (~1700 RPM) to allow for cooling when the skin temperature is rising over 40C.

I noticed that I can tolerate ~40C just fine, but 42C is not good for prolonged (more than 30 min) use. It gets annoying fast over 41C.

I replaced the mentioned USB-C to HDMI converter with a HooToo converter and that one is not getting as warm as the previous one. Also, the USB-C connector has much lower temperature than the previous one (so I guess heat transfer is not that much).

This didn't quite solve the heating issue, though.

I used iStat Menus to change the speed of the fan, so it is cooling more. With the fan speed set at ~5000 RPM, the skin temperature is around 39-40C with light use of computer (MS Word, browser -- 90% idle). I was even able to charge the computer, have it connected to the external display and use it with skin temp under 40C with the fan at its maximum speed.

IMHO, the cooling system of the MacBook Pro is not suited for "Pro" use -- at least not in a comfortable way. I believe this could easily be adjusted with an OS/firmware upgrade, so that he OS would turn the fan speed up when reaching skin temperature of 40C.

I will also give MacFanControl a try, to see if can automatically adjust the fan speed .

Answer 3

Most MacBook Pros have dual-GPUs. The more powerful AMD GPUs are required to be active when an external screen is connected and they produce significant heat. There is no way to use the internal (Intel) GPU for external screens.

To reduce heat and fan noise, however, it is possible to deactivate Intel's Turbo Booster feature for the CPU. I use Turbo Boost Switcher, which helps a bit to reduce temperature. Volta is a similar App, but does not seem to work with all MacBooks. Naturally, this comes with an approximate 15% performance hit.

Answer 4

i had same heating issue for more than 6 months till i tried this and then everything is just fine.

1. Increase fan speed to constant 4500 RPM by downloading Mac fan control app
2. Use a elevated stand while using mac. Lower metal body should have enough air circulation.

Now whether i use external display of dedicated GPU, everything just works fine without heating my Macbook pro.