CPU Stuck at 0.79 GHz when plugged into ac adapter

[RosePeach]

Hi,

I have a HP Spectre x360 Convertible 13 running Windows 10. When I plug in the wall adapter to charge the notebook the cpu frequency drops to 0.79 GHz. When I unplug the notebook the frequency behaves like normal and turbo boosts around 2.0 GHz.

Things I have tried:

Fresh install of Windows 10 - same problem

HP Support assistant to install drivers - same problem

Ubuntu 19.10 - same problem

Different power adapter - same problem

Bios update - same problem

Bios "power settings" - I have tried both "performance" and "balanced." Neither fix the problem

I have checked the CPU temperature with Aida 64 and the CPU is around 40 degrees Celsius at idle so the CPU isn't thermal throttling.

I have run the HP PC Hardware Diagnostic Windows app and all the "system" & "component" tests passed.

 I have tried HP Support suggestions to roll back the bios but that process seems to fail each time.

I am at a loss. What can I do to fix this machine? It is out of warranty so that isn't an option.

[praveen196]

@RosePeach Welcome to HP Community!

I understand that the CPU Stuck at 0.79 GHz when plugged into an ac adapter

To provide you with an accurate solution, I'll need a few more details:

Have you recently made any software or hardware changes on the PC before the issue started?

Did it happen after a software update?

Have you tried to update the drivers as well as the Bios?

Have you tried to run any test on the computer?

In the meantime, let's try these steps here:

Perform a Hard reset on the PC: 

Many startup errors and other problems can be resolved by decreasing the amount of power stored in hardware components. Decreasing stored power is sometimes referred to as a "Hard Reset". Use the following steps to perform a hard reset on a computer:

1. If Windows is open, click Start and then Shutdown.

   If Windows is not open and the computer has power, press and hold the power button on the computer until the computer shuts off.

2. With the power off, disconnect the power cord from the back of the computer.

3. With the power off and the power cord disconnected, press the power button on the computer for 5 seconds. The power light indicator on or near the power button might turn on briefly but then go out.

4. Reconnect the power cord and turn on the power.

Next thing, I would suggest here is While playing these games please check the task manager for CPU usage and end any unwanted task or process that is hogging the CPU usage a lot from this link: HP PCs - Using Task Manager (Windows 10, 

For now please perform all the prescribed steps from this link: HP Notebook PCs - Reducing Heat Inside the Laptop to Prevent Overheating

I would suggest here is to update the Bios and Chipset drivers. Also, download and install HP support assistant on your PC. It should automatically download and install the latest updates and drivers for your PC.

Refer this link to know how to use HP support assistant.

If the issue persists, I would suggest here is to run an extensive system diagnostics test from F2(Please capture the failure ID for further assistance).

Keep us posted,

If you would like to thank us for our efforts to help you, 

Give us a virtual high-five by clicking the 'Thumbs Up' icon below, followed by clicking on the "Accept as solution" on this post, 

Have a great day!

[RosePeach]

I cannot remember what happened before this started happening. I wasn't using the computer at the time. I have updated the bios to the latest version available from HPs website. This problem occurs under Windows and Linux so looking at task manager doesn't matter. Both operating systems show that the CPU frequency does not go above 0.79 Ghz when plugged into the power adapter. I have tried performing a hard reset and it does not fix the problem.

[praveen196]

@RosePeach

I understand your concerns.

In that case, I would suggets you contact our phone support and check for the support option. They will help you.

Here is how you can get in touch with phone support.

1)Click on this link - www.hp.com/contacthp/

2)Select the product type.

3)Enter the serial number of your device or select let HP detect your product option.

4)Select the country from the drop-down.

5)You should see the HP phone support number or Chat option listed.

We are experiencing longer than expected wait times to reach an agent due to the CoViD-19 impact and there might have been issues in you getting the expected resolution on the issue. 

Have a nice day!!