When I run sensors I get:

Adapter: Virtual device
temp1:        +56.0°C  (crit = +102.0°C)

Adapter: ISA adapter
Physical id 0:  +55.0°C  (high = +86.0°C, crit = +100.0°C)
Core 0:         +50.0°C  (high = +86.0°C, crit = +100.0°C)
Core 1:         +52.0°C  (high = +86.0°C, crit = +100.0°C)

I have a quad-core i5 processor.

How do I identify what Physical id 0 and temp1 stand for?

2 Answers 2


Physical id 0 is your CPU

Core0 is your first individual core

Core1 is your second individual core

  • What about core 3 and 4? I have a quad-core i5 processor.
    – To Do
    Aug 2, 2014 at 8:41
  • @ToDo I believe two of those cores are virtual cores, although, I could be mistaken. Only physical cores have temperatures. To be sure, go ahead and run sudo sensors-detect follow the instructions closely just don't agree yes to the one that's "risky".
    – mchid
    Aug 2, 2014 at 8:48
  • 1
    And what about temp1?
    – To Do
    Jul 11, 2016 at 10:29

From (tomshardware.com - Is Intel i5 Dual Core or Quad Core?) you get this answer:

i5-750 is a quad core, all other i5s are dual cores, albeit with hyperthreading.

That answer is from 2010 but you get the point. All i7's are definitely quad core.

The next answer on the same link goes on to say:

what he said, Intel is confusing uneducated customers this time around. I do not mean uneducated = stupid either, i mean that the average user that walks into best buy who does not know what to look for in a CPU...

Based on reporting from sensors you almost certainly have a dual core processor.

My i7 processor from 2012/2013 is reported correctly:

$ sensors
Adapter: Virtual device
Processor Fan: 3906 RPM
CPU:            +80.0°C  
Ambient:        +48.0°C  
GPU:            +67.0°C  
Other:          +77.0°C  

Adapter: Virtual device
temp1:        +27.8°C  (crit = +106.0°C)
temp2:        +29.8°C  (crit = +106.0°C)

Adapter: ISA adapter
Physical id 0:  +82.0°C  (high = +87.0°C, crit = +105.0°C)
Core 0:         +82.0°C  (high = +87.0°C, crit = +105.0°C)
Core 1:         +80.0°C  (high = +87.0°C, crit = +105.0°C)
Core 2:         +77.0°C  (high = +87.0°C, crit = +105.0°C)
Core 3:         +73.0°C  (high = +87.0°C, crit = +105.0°C)

I have a huge problem with temperatures and fan speed, but the number of cores are correct.

If you doubt sensors you can double check using:

ls /sys/devices/system/cpu/
cpu0  cpu3  cpu6     cpuidle       isolated    modalias  possible  uevent
cpu1  cpu4  cpu7     hotplug       kernel_max  offline   power
cpu2  cpu5  cpufreq  intel_pstate  microcode   online    present

With a dual core (hyper-threading) you'll see CPU0 to CPU3. In this example it's a quad core so CPU0 to CPU7 appear.

To answer your second question of Temp 1 note that sensors is missing one of the temps in my situation which you can confirm on your platform by using:

$ cat /sys/class/thermal/thermal_zone*/temp

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