HP Z8 G4 Win10 system fans too fast

[Frustrated92]

In Dec 2018 our office received 6 new HP Z8 G4 Workstations.  Three  of the computers have experienced this issue with the fan running faster and noiser after a large pdf file has been opened.  The fan does not slow down even after all apps are closed.  Our IT dept has not been able to figure out a remedy for this irritating problem.  So far the only way to get the fan running at normal quit speed is to shut-down and restart the computer.

[BambiBoomZ]

Frustrated92,

The problem may or may not be thermal sensor-related, but regardless, those are expensive systems under a comprehensive warranty. Have HP support at your office as soon as possible.  In the meanitime, consider running HWMonitor or similar when working with the files mentioned and watch CPU and GPU temperatures.  If they are not excessive, then the fault is tempertures sensors or possibly a BIOS glitch. There is some possibility the motherboards would need replacing.  

Strangely parallel, I notice CPU fan speed increase in the office z620 (E5-1680 v2 8C@ 4.3GHz w/ z420 liquid cooler) and slight coil whine on the GTX 1070 Ti  only when converting large files, e.g., 120MB documents with images, to PDF's (Acrobat DC).  Those must must be very compute demanding,  but I have monitored temperatures and the CPU shows 100% on 5-6 cores but never over about 63-65C  This is not nearly as demanding as rendering, but there may be some extreme but very brief peaks.

BambiBoomZ

[Frustrated92]

Thank you.  I will forward your suggestions to our IT department here at the Corps of Engineers since non-IT users are unable to install apps or to change system settings.

[Frustrated92]

Sorry I don't have any further news on the matter since forwarding your suggestion to our IT department.  So far the fast running fan and noise has only happened once after a Windows update was installed. 

[BambiBoomZ]

Frustrated92,

Thank you for the update.

The intermittent characteristic is worrying - unpredictable function is the negation of the basic workstation design basis, 

If I might suggest, this makes an accurate diagnostic by HP technicians all the more critical. Failing temperature sensor(s) mis (over) reporting CPU temperatures still seems the most likely explanation, but that would quite unusual and there's an equal possibility that a BIOS glitch may be responsible as the fans are controlled there. 

If consistent, that malfunction is not likely to cause damage, but if the failure had the reverse action and under-reported the temperature, the CPUs' memory controller could be "fried" under full load, such as: dynamic stress, particle, gas flow, thermal , and etc. simulations. 

BambiBoomZ