Core temperature above threshold

[68546.319229] CPU1:  Core temperature above threshold, cpu clock throttled (total events = 189995)
[68546.319240] CPU0:  Core temperature above threshold, cpu clock throttled (total events = 189989)
[68546.519121] CPU0:  Core temperature above threshold, cpu clock throttled (total events = 192228)
[68546.519131] CPU1:  Core temperature above threshold, cpu clock throttled (total events = 192234)

I checked to see if the lm_sensors package was installed on the system, so I could check fan speeds and the central processing unit (CPU) temperature. It wasn't installed, so I installed it from the root account with yum install lm_sensors.

# yum install lm_sensors
Loaded plugins: fastestmirror, langpacks
Loading mirror speeds from cached hostfile
 * base: mirror.cogentco.com
 * epel: mirror.us.leaseweb.net
 * extras: cosmos.illinois.edu
 * updates: cosmos.illinois.edu
Resolving Dependencies
--> Running transaction check
---> Package lm_sensors.x86_64 0:3.3.4-11.el7 will be installed
--> Finished Dependency Resolution

Dependencies Resolved

================================================================================
 Package             Arch            Version                Repository     Size
================================================================================
Installing:
 lm_sensors          x86_64          3.3.4-11.el7           base          137 k

Transaction Summary
================================================================================
Install  1 Package

Total download size: 137 k
Installed size: 409 k
Is this ok [y/d/N]: y
Downloading packages:
lm_sensors-3.3.4-11.el7.x86_64.rpm                         | 137 kB   00:00
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
  Installing : lm_sensors-3.3.4-11.el7.x86_64                               1/1
  Verifying  : lm_sensors-3.3.4-11.el7.x86_64                               1/1

Installed:
  lm_sensors.x86_64 0:3.3.4-11.el7

Complete!
#

I then ran the sensors command, which is part of the lm_sensors package, and saw the following output:

# sensors
atk0110-acpi-0
Adapter: ACPI interface
Vcore Voltage:      +1.23 V  (min =  +0.85 V, max =  +1.60 V)
 +3.3 Voltage:      +3.33 V  (min =  +2.97 V, max =  +3.63 V)
 +5 Voltage:        +5.09 V  (min =  +4.50 V, max =  +5.50 V)
 +12 Voltage:      +12.51 V  (min = +10.20 V, max = +13.80 V)
CPU FAN Speed:     1102 RPM  (min =    0 RPM, max = 7200 RPM)
CHASSIS FAN Speed:    0 RPM  (min =  800 RPM, max = 7200 RPM)
CPU Temperature:    +66.5°C  (high = +60.0°C, crit = +95.0°C)
MB Temperature:     +54.0°C  (high = +45.0°C, crit = +95.0°C)

#

I saw "0 RPM" for the chassis fan speed, which was of concern, since I expected it to be spinning and cooling the components inside the computer case. And when I checked the sensor readings again over an hour later, I saw the CPU temperature was considerably higher.

# sensors
atk0110-acpi-0
Adapter: ACPI interface
Vcore Voltage:      +1.24 V  (min =  +0.85 V, max =  +1.60 V)
 +3.3 Voltage:      +3.31 V  (min =  +2.97 V, max =  +3.63 V)
 +5 Voltage:        +5.09 V  (min =  +4.50 V, max =  +5.50 V)
 +12 Voltage:      +12.46 V  (min = +10.20 V, max = +13.80 V)
CPU FAN Speed:     1196 RPM  (min =    0 RPM, max = 7200 RPM)
CHASSIS FAN Speed:    0 RPM  (min =  800 RPM, max = 7200 RPM)
CPU Temperature:    +73.5°C  (high = +60.0°C, crit = +95.0°C)
MB Temperature:     +54.0°C  (high = +45.0°C, crit = +95.0°C)

#

I booted into the BIOS setup prior to opening the computer's case and saw the following:

Hardware Monitor

CPU Temperature	[82.5°C180.5°F]
MB Temperature	53°C/127°F]

CPU Fan Speed (RPM)	1231RPM]
CPU Q-Fan Control	[Disabled]
Chassis Fan Speed (RPM)	[N/A]

VCORE Voltage	[ 1.256V]
3.3V Voltage	[ 3.312V]
5V Voltage	[ 5.094V]
12V Voltage	[ 12.460V]

When I opened the system, I found that neither the CPU fan in the front of the case nor the one in the back of the case were spinning. It seemed odd to me that they would both fail at once, but it is possible one failed first unnoticed and then the other failed later. I vacuumed dust from the PC case vents and from the top of the heat sink beneath the CPU fan. After I cleaned dust from the CPU heat sink and restarted the system, when I checked the system again after it had been running for about an hour I saw a much lower CPU temperature reading.

$ sensors
atk0110-acpi-0
Adapter: ACPI interface
Vcore Voltage:      +1.24 V  (min =  +0.85 V, max =  +1.60 V)
 +3.3 Voltage:      +3.33 V  (min =  +2.97 V, max =  +3.63 V)
 +5 Voltage:        +5.09 V  (min =  +4.50 V, max =  +5.50 V)
 +12 Voltage:      +12.46 V  (min = +10.20 V, max = +13.80 V)
CPU FAN Speed:     1638 RPM  (min =    0 RPM, max = 7200 RPM)
CHASSIS FAN Speed:    0 RPM  (min =  800 RPM, max = 7200 RPM)
CPU Temperature:    +48.5°C  (high = +60.0°C, crit = +95.0°C)
MB Temperature:     +52.0°C  (high = +45.0°C, crit = +95.0°C)

$

I'll replace both of the fans, but for now at least the CPU temperature has dropped after I removed dust from the heat sink.