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macrumors newbie
Original poster
Nov 23, 2020
When I look at the temperature of my iMac running Big Sur using the powermetrics tool from the terminal I notice there are figures for the CPU Thermal Level and GPU Thermal level. They are not the temperature, but do seem to increase when the computer is under load. My searching online has not given any good answers, but does anyone know what those numbers actually represent?

Here's some example output:

% sudo powermetrics --samplers smc -i1 -n1
Machine model: iMac19,1
SMC version: 2.46f13
EFI version: 1554.3.0
OS version: 20D91
Boot arguments:
Boot time: Fri Apr  2 15:20:37 2021

*** Sampled system activity (Wed Apr  7 21:22:39 2021 -0400) (7.16ms elapsed) ***

**** SMC sensors ****

CPU Thermal level: 0
GPU Thermal level: 0
IO Thermal level: 0
Fan: 1198 rpm
CPU die temperature: 47.42 C
GPU die temperature: 41.00 C
CPU Plimit: 0.00
GPU Plimit (Int): 0.00
GPU2 Plimit (Ext1): 0.00
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