[iMac] CPU temp: -127.0ºC

[lucasfais]

First of all, really nice project! Congrats man.

I think it isn't identifying the correct CPU sensor for my iMac. Maybe TC0C?

Machine info:

[lucasfais]

I just realised there are TC0C and TC1C, one for each core. It seems the other apps use the CPU Heatsink temperature TC0H.

[Chris911]

By default iStats uses TC0P for the CPU temperature. It's highly possible that the sensor key was different in 2009.

[scott-joe]

Also a huge fan. This is awesome. Thanks for writing this. I needed something simple like this bc I was performing a build and wanted to keep an eye on things, but the CPU read out from TC0P was 67°C but each core was reading between 87°C and 93°C... I'm just wondering if you know whether the proximity sensor is considered more accurate than the core temperature readings.

I'd appreciate any insight into the way these hardware temperature measurements work. Thanks again for your work on this and any feedback you can find the time to provide.

[Chris911]

Hi @scott-joe, as far as I know there's not much official information about the hardware sensors. The only resource I can link to is this one which contains some of the available keys and a their name but that's it.

iStats supports the extra command to scan for the sensors you think are the more relevant so I encourage you to use that feature to get exactly the information you want.

[scott-joe]

@Chris911 That's what I ended up doing and I appreciate the flexibility you've built in. Thanks for the link. I'll look it over.

[davidak]

same issue.

$ istats scan
[...]
$ istats enable all
$ istats all
--- CPU Stats ---
CPU temp: -127.0°C  ▁▂▃▅▆▇

--- Fan Stats ---
Total fans in system: 3
Fan 0 speed: 998.75 RPM  ▁▂▃▅▆▇
Fan 1 speed: 2220.5 RPM  ▁▂▃▅▆▇
Fan 2 speed: 2488.5 RPM  ▁▂▃▅▆▇

--- Battery Stats ---
No battery on system

--- Extra Stats ---
Tm0p Misc (clock chip) Proximity temp: 55.13°C  ▁▂▃▅▆▇
Tm0P Unknown temp: 55.13°C  ▁▂▃▅▆▇
Tp1P Unknown temp: 61.5°C  ▁▂▃▅▆▇
Tp2H Unknown temp: 73.0°C  ▁▂▃▅▆▇
Tp3H Unknown temp: 62.13°C  ▁▂▃▅▆▇
TA0p Ambient temperature temp: 33.25°C  ▁▂▃▅▆▇
TA0P Ambient temperature temp: 28.36°C  ▁▂▃▅▆▇
TA0V Unknown temp: 28.3°C  ▁▂▃▅▆▇
TA1v Unknown temp: 32.7°C  ▁▂▃▅▆▇
TC0C CPU 0 Core temp: 73.42°C  ▁▂▃▅▆▇
TC0D CPU 0 Die temp: -127.0°C  ▁▂▃▅▆▇
TC0H CPU 0 Heatsink temp: 56.88°C  ▁▂▃▅▆▇
TC0P CPU 0 Proximity temp: -127.0°C  ▁▂▃▅▆▇
TC1C Core 1 temp: 73.0°C  ▁▂▃▅▆▇
TG0p Unknown temp: 62.0°C  ▁▂▃▅▆▇
TG0D GPU 0 Die temp: 64.75°C  ▁▂▃▅▆▇
TG0H GPU 0 Heatsink temp: 61.5°C  ▁▂▃▅▆▇
TH0O Unknown temp: 8.0°C  ▁▂▃▅▆▇
TH1O Unknown temp: 7.22°C  ▁▂▃▅▆▇
TLAV Unknown temp: 53.75°C  ▁▂▃▅▆▇
TLBV Unknown temp: 51.81°C  ▁▂▃▅▆▇
TLCV Unknown temp: 50.2°C  ▁▂▃▅▆▇
TL0p Unknown temp: 58.88°C  ▁▂▃▅▆▇
TL0P LCD Proximity temp: 47.45°C  ▁▂▃▅▆▇
TL0V Unknown temp: 50.2°C  ▁▂▃▅▆▇
TL1V Unknown temp: 46.53°C  ▁▂▃▅▆▇
TL2V Unknown temp: 53.75°C  ▁▂▃▅▆▇
TO0p Unknown temp: 50.5°C  ▁▂▃▅▆▇
TO0P Optical Drive Proximity temp: 49.5°C  ▁▂▃▅▆▇
TPCD Platform Controller Hub Die temp: 66.0°C  ▁▂▃▅▆▇
TS0V Unknown temp: 50.42°C  ▁▂▃▅▆▇
TS2p Unknown temp: 53.13°C  ▁▂▃▅▆▇
TS2P Unknown temp: 53.13°C  ▁▂▃▅▆▇
TS2V Unknown temp: 50.52°C  ▁▂▃▅▆▇

---

iMac (27 Zoll, Mitte 2010) OS X 10.10.5

[Chris911]

Thanks for the scan results @davidak. I think what I'll do is fallback on another sensor for the CPU temp if TC0P returns a negative value. However I'm not really sure which sensor to use. TC0C (core temp) and TC0H (heatsink) both return values but they're quite different. I guess the core temp is the most relevant.

[Chris911]

@lucasfais which other app is using TC0H?

[lucasfais]

iStats Menus shows "CPU Heatsink" as the default sensor, for example.

[spotlightishere]

I have the same issue here, with a 24-inch, Mid 2007 iMac. I would think that the CPU core temp would be the most relevant temperature to display on models that have it. However, to add even more, I don't have that option. For me, it would appear that Heatsink would be the best.

Available options:

--- CPU Stats ---
CPU temp: -127.0°C  ▁▂▃▅▆▇

--- Fan Stats ---
Total fans in system: 3
Fan 0 speed: 698.25 RPM  ▁▂▃▅▆▇
Fan 1 speed: 1313.5 RPM  ▁▂▃▅▆▇
Fan 2 speed: 1423.25 RPM  ▁▂▃▅▆▇

--- Battery Stats ---
No battery on system

--- Extra Stats ---
Tm0P Unknown temp: 63.13°C  ▁▂▃▅▆▇
Tp0P PowerSupply Proximity temp: 82.72°C  ▁▂▃▅▆▇
TA0P Ambient temperature temp: 29.13°C  ▁▂▃▅▆▇
TC0D CPU 0 Die temp: -127.0°C  ▁▂▃▅▆▇
TC0H CPU 0 Heatsink temp: 61.5°C  ▁▂▃▅▆▇
TC0P CPU 0 Proximity temp: -127.0°C  ▁▂▃▅▆▇
TG0D GPU 0 Die temp: 75.0°C  ▁▂▃▅▆▇
TG0H GPU 0 Heatsink temp: 69.5°C  ▁▂▃▅▆▇
TG0P GPU 0 Proximity temp: 70.0°C  ▁▂▃▅▆▇
TG1D GPU 1 Die temp: -127.0°C  ▁▂▃▅▆▇
TH0P Harddisk 0 Proximity temp: 54.63°C  ▁▂▃▅▆▇
TL0P LCD Proximity temp: 51.88°C  ▁▂▃▅▆▇
TO0P Optical Drive Proximity temp: 43.88°C  ▁▂▃▅▆▇
TW0P AirPort Proximity temp: 61.5°C  ▁▂▃▅▆▇

[grafkaal]

Thanks for an excellent utility! I've got an iMac (27-inch, Late 2009) and am having the same negative value on TC0C and TC0D TC0C CPU 0 Core -127.0°C ▁▂▃▅▆▇ TC0D CPU 0 Die -127.0°C ▁▂▃▅▆▇ TC0H CPU 0 Heatsink 34.75°C ▁▂▃▅▆▇ Other than that it has helped me so much as I have to be able to check the system when away. In an ideal world, I'd have TC0H as the default CPU Temp! Is there any way to alter to TC0H ourselves? Many thanks.