15-eu0005na laptop CPU throttled to 400 Mhz

[turf00]

So I have a problem with my HP Envy 15-eu0005na. It will frequently just throttle the CPU to 400 Mhz and then keep the CPU speed there "forever".

The only way I have found to fix the problem, when it occurs, is to shutdown then start the laptop again. Even a restart will not fix the issue.

This problem occurs in both Windows 11 and Ubuntu. It is therefore not related to Windows drivers or installs. It happen after restoring Windows to its initial setup.

There doesn't seem to be a pattern to when this occurs specifically, it happens when connected to mains power or on battery. I frequently notice it just with watching a youtube video, not even doing anything that taxing for the CPU.

A CPU temperature monitor shows it can happen even when the CORE temp is not that high. 40-50c

I have had my laptop returned to HP and they replaced the main board, but the problem still occurs just the same.

I personally did not encounter this issue until late last year and I bought my laptop at the end of 2021 with an extended support contract. Therefore, I assume that some Bios update that I have applied has caused the issue or caused it to happen frequently.

I would like to revert the Bios updates but the latest update states that its not possible to roll back. I am on 

F.14 Rev.A

I would appreciate assistance, but like I said above have already had the laptop returned and the motherboard replaced already.

Any help appreciated, but pretty unsure if I would ever recommend buying HP again at this point.

[Irwin6]

Hi @turf00,

Welcome to the HP Support Community.

Thank you for posting your query, I will be glad to assist you.

I see that you are facing an issue with your Laptop.

Please follow the steps below to perform an extensive system test to confirm if the hardware is working fine.

1) Shut down the computer.

2) Turn the computer back on again and repeatedly tap on the ESC until a Startup menu appears.  

3) Press F2 once.  

4) Go to the system test > extensive test

If the hardware is working fine. Kindly refer to the steps on this link to perform a recovery and let me know if that resolves the issue. (Take a backup of the data before performing a recovery)

Please mark this post as “Accepted Solution” if the issue is resolved and if you feel this reply was helpful click “Yes”.

I hope this helps.

Take care and have a great day ahead!

Irwin6

HP Support

[turf00]

Hi

I completed the extensive test as you requested and it passed.

I have previously already performed a Windows recovery and it made no difference, as I state in the post the problem occurs on Ubuntu as well.

What we have tried:

1. Resetting Windows via recovery

2. Laptop sent back and motherboard replaced.

Any other ideas?

Thanks,

Justin

[Irwin6]

Hi @turf00,

I am sorry to hear that the above steps did not help much but i do appreciate your efforts in performing the troubleshooting steps.

The support on the HP community is currently available within certain constraints. We are striving to enhance our assistance and broaden its scope. We appreciate your understanding and patience.

I've sent you a private message with the instructions. In order to access your private messages, Click the Private message icon on the upper right corner of your HP Community profile Next to your profile Name, you should see a little blue envelope, please click on it or simply click on this link

Take care and have a great day ahead!

Irwin6

HP Support

[turf00]

Further Investigation

I've dug further into this issue. There are two problems with the laptop as it stands, one occurs infrequently but makes the laptop unusable without a shutdown. The other occurs every 5-10s.

These two problems may be related to each other, which seems likely.

Problem 01

CPU is dropping down to 400Mhz every 5-10s due to thermal issues. It remains at this speed only very briefly. 

Having monitored this via HWiNFO, I can see that the reason reported is PROCHOT EXT, which according to HWiNFO means that some component external to the CPU is reporting an issue, rather than the processor itself.

Both the processor and the GPU remain at low temperatures when this happens.

In the screenshot above, the two main graphs of interest are Thermal Throttling (PROCHOT EXT) and Core Clocks. You can see that the CPU is dropping sharply (to 400Mhz) and then returning back up in alignment with the Thermal Throttling. So the throttling happens very quickly and then is off before returning some seconds later.

The laptop is idling, rather than being under load at the time. You can see in the CPU temp and GPU temp that they are nowhere near the limits where the fan would be required.

In the physical world, when the throttling kicks in, you can actually hear the fan spin up very briefly <1s before it suddenly cuts out. This spin up is aligned with the PROCHOT EXT thermal events seen in the graph above.

Here is the current sensor status from HWiNFO showing that PROCHOT EXT has been set in the past since the tool was running.

Problem 02

In this case, the Thermal event PROCHOT EXT (same as the above) occurs and never turns off (without full shutdown, it will remain during reboot). The CPU cores remain fixed at 400 Mhz making the laptop useless and requiring a shutdown.

Here are the graphs showing this case from HWiNFO:

In this case the PROCHOT EXT will always stay on and the CPU (all cores) are throttled to 400 Mhz until a shutdown occurs. This was taken when the laptop was idling. You can see that both the CPU and CPU temperature are low when this happens and during the event.

[turf00 · Accepted solution]

I sent my laptop back to HP and it now appears fixed. They replaced the following hardware:

Motherboard, battery, IR board, IR cable.

Both problems outlined above now appear fixed, I don't see the the PROCHOT EXT event taking place every couple of seconds and I have not encountered the issue with the CPU being throttled constantly.