little update on my tests in case you're interested. i also used an external usbC multimeter to check voltage and amps on the port.
MBP 2019 16", intel+AMD
in a nutshell, everything is fine until you run on the intel gpu (so only one display). AMD gpu, without connection, is stable betweene 0.1W and 4.5W . also overloading the cpu over 60% of utilization on total processes makes no great deal on the fans speed. even using some process to stress the intel GPU the fans are quite slow.
when the second AMD GPU is engaged and you have some process who needs the gpu support:
- if you force to use it on the interal display from terminal (so no connection to another display) and the cpu% >60% of total process the fans speed up from 2.4k rpm and 4k rpm (usually average on 3k).
- if you have internal and external display connected, everything is fine until the cpu is under <60%. after that the fans rpm will go up.
i tried several display, brands, resolution (
you can simply try to have the MBP with only a safari tab on some website with javascript animations (i tried feedly).
using the intel gpu or the clamshell mode (so using only the external display) everthing is fine. you can check on the activity monitor and istat that:
cpu will go on 60%, GPU is being engaged (also GPU time will go up). the fans will be on 1.8K and 2.4k average.
having both display turned on, the wattage will increase a bit, but the fans will speed up over 3.5k~4k,.
close the lid, or disconnecting the second display, will cause the fans to go way down to 1.8 (with the webpage still opened).
the question is: is this normal? why a process that is not stressing the intel gpu, is so harsh on the AMD?
of course the problem is not in the page but probably there's a sum of events or processes that is causing the logic board to think that more fan speed is necessary.
i also checked the electric network, also used an UPS to provide distinct power supply for the display or the MBP, checked absorbtion with multimeter, etc. but this behavior is every time the same in these conditions.
let me know if someone will try, i hope this will be helpful to someone
regards