Discrepancy between TC0P and actual CPU temperature

[sjlevine]

Hi again Mikael! I have a separate issue with macfanctld I'd like to bring to your attention. On my hardware (a MacbookPro10,1 - quad-core i7 released in 2012), I find that the temperature reported by TC0P is consistently much lower than the actual CPU core temperatures. Here's an example of running the sensors command when my CPU is getting toasty:

$ sensors
coretemp-isa-0000
Adapter: ISA adapter
Physical id 0:  +69.0°C  (high = +87.0°C, crit = +105.0°C)
Core 0:         +69.0°C  (high = +87.0°C, crit = +105.0°C)
Core 1:         +68.0°C  (high = +87.0°C, crit = +105.0°C)
Core 2:         +62.0°C  (high = +87.0°C, crit = +105.0°C)
Core 3:         +62.0°C  (high = +87.0°C, crit = +105.0°C)

applesmc-isa-0300
Adapter: ISA adapter
Left side  : 6201 RPM  (min = 6200 RPM)
Right side : 6200 RPM  (min = 6200 RPM)
TB0T:         +30.2°C  
TB1T:         +30.2°C  
TB2T:         +29.0°C  
TC0E:         +69.8°C  
TC0F:         +71.5°C  
TC0P:         +47.8°C  
TC1C:         +68.0°C  
TC2C:         +68.0°C  
TC3C:         +59.0°C  
TC4C:         +66.0°C  
TCFC:          +0.0°C  
TCGC:         +69.0°C  
TCSA:         +63.0°C  
TCTD:          +0.0°C  
TCXC:         +69.8°C  
TG0D:         +57.2°C  
TG0P:         +52.5°C  
TG1D:         +62.0°C  
TG1F:         +61.2°C  
TG1d:         +56.0°C  
TH0A:         +64.0°C  
TH0B:         +64.0°C  
TH0V:         +41.5°C  
TH0a:         +64.0°C  

Please note that the core temperatures reported via the first method are over 20°C higher than TC0P. I'm not sure, but I'm also guessing that the TC1C, TC2C, TC3C, and TC4C are probably the sensors for my different cores. Perhaps Apple moved the TC0P sensor to be physically farther from the CPU on newer hardware iterations? I don't know how to verify this or what all of the sensors above represent, but it does look that TC0P isn't an accurate assessment of CPU temperature on my hardware.

I wanted to see if you have any advice regarding possible fixes / patches? I'd be happy to help out / test any changes on my hardware.

Thanks!

Cheers, Steve

[mck182]

Hey @sjlevine, did you ever get to the bottom of this? I noticed the same issue on my Macbook Pro mid-2014 model - the TC0P is ~20°C lower than Cores...

[sjlevine]

Hello again,

This was such a long time ago that unfortunately I can't remember clearly! I don't know if I ever came up with a good reason why that one sensor was different than the others, but I did have a work-around where macfanctld could turn on my fan when appropriate. I believe I did that by playing around with the config file.

Sorry I can't be of more help!