HP 405 G6 DM overheats and shuts down

[NippyDripple]

Hi!

I've got a brand new 405 G6 DM. Latest BIOS, OS and drivers. 

When it works, it works fine. Occasionally, no matter the load it would just shut down abruptly without even a trace or a hint in the Event Viewer!

I swapped RAM and the factory provided 65W nPFC charger to no avail.

When I put my hand on the grill in the back of the case, I can feel only a very light airflow even if the CPU is hot. There is a ton of fresh air available around the case and zero dust on the filters or on the fan.

As @NightWalkerbg mentioned in https://h30434.www3.hp.com/t5/Desktop-Boot-and-Lockup/Is-there-a-way-to-control-the-CPU-Colling-fan/... I think there is a flaw with the CPU fan speed control.

I'm pretty sure HP is moving lots of these units and I wonder how many people using them have the same issue?

[BeemerBiker]

You should have a 4 pin fan like this one.

When powering up the fan should spin at a high speed then drop down to a lower speed.

Go into the BIOS setup and try setting the idle speed of the fan higher then reboot.

If there is no change in fan speed then yes, a problem.  

Possibly the system in running in turbo mode all the time. Go into the power setup and change the power setting to prevent it from running at %100 all the time..

Try %75 for maximum processor performance

make sure minimum is %5 and not %100

You also need to monitor the temperatures to verify the problem is fixed

download and install tthrottle https://efmer.com/download-tthrottle/

It will determine the max temp and prevent the temp from rising above it.

If none of the above work AND TTHROTTLE shows it is having to slow down the CPU then you need an adapter to force the fan to run at the full 12v settings.

Post back here on how to mod this to work with your 4 pin fan and force high speed.

[NippyDripple]

Thanks for the reply, @BeemerBiker!

I tried setting the CPU fan to 70% in idle via the BIOS setting.  The results are only getting weirder IMO.

With the PC fully shut down, once I press the power button I can hear the CPU fan briefly (~0.5s) spinning up to high RPM and then going down. Shortly after the BIOS fan setting kicks in and it goes to a constant speed.

The boot RPM are audibly higher than the 70% idle setting but I don't know by how much.

I'm technically savvy, with a Ph.D. in electrical engineering. Modding the CPU fan is easier for me than for my toddler to suck on its pacifier. 🙂 The problem is that what I'm seeing doesn't seem to be making much sense. It doesn't register as a thermal or an electrical issue, yet is has to be one.

Another odd thing is that there is no audible change in the RPM in Windows 11, no matter if the PC is running a heavy app (Excel, Power BI, Blender, Chia plotting, etc.) or just sitting in absolute idle. The fan speed never seems to change no matter the CPU/GPU load!

I swapped the RAM and the NVMe SSD but to no avail. Results are the same. I need to find another power brick with a black tip (I only have blue tips) to see if it is causing this, or as a last resort I'll slice the cable and hook a logging multimeter to see if there is anything funky going on with the power going in.

The only interesting thing I think I found is the flappy FCLK and UCLK. This chart is taken over 3 days period where the PC was plotting Chia on a NAS.  It was taken by HWiNFO64's logging of the system and then some Power BI for the chart itself.

Mem multiplier and memory clock were fine, at least according to the log. No errors or throttling either. Temps and voltages were also seemingly in check. 

Let me know if you want me to upload the whole log.

Anyway, it seems there is some issue with the CPU, VRM, mobo, power, heatsink seating or God knows what.

I'd send it for repair ASAP but I first need to check how is the intl. warranty coverage. I purchased it customized in the U.S. and then I sent it abroad.

Even though HP claim it's under warranty I need to check if my local HP office will validate it.

In the meantime, any ideas are welcome!

[BeemerBiker]

Please run that temperature app I recommended. 

https://efmer.com/download-tthrottle/

In addition to reporting temps it will slow down the CPU to prevent it from overheating.

The fact the CPU fans RPM do not increase indicate the system is not aware of a CPU problem or cannot speed the fan up due to a faulty drive or bad design.

Is there a system fan that expels air out the back?  Make sure it is not blocked and is working correctly.