CPU stuck at 0,4 GHz when plugged in

[Mel-pavillion]

Hp Pavillion gaming 15 ec series with ryzen 3550H stuck at 0,4 GHz only when plugged in. It goes up to normal speed immediately after unplugging. Diagnostics say i have broken AC Adapter, but i have already replaced it and nothing changed. Is it possible that it is trying to protect itself by lowering the speed, and if so, can it be disabled somehow?

i have already tried windows, driver and BIOS update, all HP support assistants and diagnostics, resetting the laptop to factory settings, changing the power plan, running it without a battery... Please it is a common problem and it´s about time to be solved.

[zoey7886]

@Mel-pavillion, Welcome to the HP Support Community!  

Thanks for reaching out about your query regarding HP Pavilion Gaming laptop! 

We're thrilled to have the opportunity to assist you and provide a solution.  

I understand how frustrating this issue must be, especially when you've already tried so many troubleshooting steps. Let’s go over a few more possibilities and see if we can get your HP Pavilion Gaming 15 running at full speed when plugged in.

Since your diagnostics initially flagged a faulty AC adapter but replacing it didn’t help, it's possible the system is still limiting performance as a safety measure. Here are a few things to check:

Check HP Command Center / BIOS Power Settings

• Some HP gaming laptops have a setting in the BIOS or HP Command Center that limits CPU performance when plugged in to prevent overheating. If you haven't already, try checking for any "Performance Mode" or "Cooler Boost" settings in these menus.

Try a Different Power Adapter / Outlet

• Even though you've replaced the adapter, it's worth testing with another one if possible (preferably an original HP adapter with the same wattage). Also, plug it into a different wall outlet to rule out power fluctuations.

Throttling Due to Overheating or Battery Issues

• Since you've already tested without the battery, let's check thermal performance. If the system is detecting high temps, it may be throttling to prevent damage. You can use HWMonitor to check if temps are unusually high when plugged in. If so, repasting the thermal paste or cleaning the vents might help.

EC / Embedded Controller Reset

• Sometimes, the system’s embedded controller (which manages power and performance) can get stuck. Try this reset:
  • Shut down the laptop
  • Unplug everything, including the battery (if removable) and AC adapter
  • Hold the power button for 30 seconds
  • Plug it back in and power it on  

Let me know how it goes!

Take care, and have an amazing day!  

Did we resolve the issue? If yes, Please consider marking this post as "Accepted Solution" and click "Yes" to give us a helpful vote - your feedback keeps us going!  

Regards, 

[Mel-pavillion]

Unfortunately none of the things you mentioned worked. I don´t have an HP Command center or any power related settings in my BIOS. The temperetaures displayed in HWmoniitor didn´t change significantly either. I tried the reset  as well but nothing changed.

[zoey7886]

@Mel-pavillion, Thank you for getting back and letting me know the steps you've tried so far — I understand how frustrating this must be, especially when you've already covered so many bases. Let's keep working on it and see if we can figure this out together.

Since the diagnostics originally flagged a faulty AC adapter, but replacing it didn’t help, it’s possible that the system is still stuck in a protective state or there’s an underlying power regulation issue. Let’s try a couple more things that might help:

Try Disabling CPU Throttling via Power Settings

• Go to Control Panel > Power Options.
• Select Change Plan Settings for the plan you’re using.
• Click on Change Advanced Power Settings.
• Expand Processor Power Management and check both Minimum Processor State and Maximum Processor State — try setting both to 100% when plugged in.
• Also, check if there’s an option under System Cooling Policy — if available, set it to Active.

Check for AMD Ryzen-Specific Settings

Sometimes Ryzen processors have their own power settings that might cause this behavior.

• Open AMD Ryzen Master (if installed) or download it from AMD’s website.
• Check if there are any performance profiles or ECO modes enabled — try switching to a high-performance profile.

Check for Power Throttling in Windows

• Open Task Manager (Ctrl + Shift + Esc).
• Go to the Performance tab and select CPU.
• See if the CPU speed is labeled as "throttled" — if it is, Windows might be limiting the power draw due to battery health or power settings.
• If so, go to Settings > System > Power & Sleep > Additional Power Settings and select High Performance or Ultimate Performance (if available).

Try a Clean Boot

Sometimes third-party software can interfere with power settings.

• Type msconfig in the search bar and open System Configuration.
• Under the Services tab, check Hide all Microsoft services and then click Disable All.
• Under the Startup tab, click Open Task Manager and disable all startup items.
• Restart your laptop and see if the CPU behavior improves when plugged in.

If none of this works, it might be worth checking if the BIOS version is up to date or if any firmware updates are available from HP support website.

Let me know how it goes — we’ll get to the bottom of this! 😊

Did we resolve the issue? If yes, Please consider marking this post as "Accepted Solution" and click "Yes" to give us a helpful vote - your feedback keeps us going!  

Regards, 

[Mel-pavillion]

I´ve already set the power settings to maximum and there is no system cooling policy option. Unfortunately i cant run AMD Ryzen on my laptop, it doesnt allow it. In the task manager the CPU isnt labeled as throttled. I have disabled everything except microsoft services in the system configuration. I have already downloaded the newest BIOS update, but unfortunatelly the problem didnt go away.

Thank you for your help.

[zoey7886]

@Mel-pavillion, Welcome to the HP Support Community! 

We're here to help you tackle that CPU stuck at 0,4 GHz when plugged in! Don't worry, we've got your back! 

To get you the best assistance, we need to take this conversation to a private chat. We're inviting you to a private message to protect your privacy and ensure that any sensitive information remains confidential. 

To access your private message, just click the little blue envelope icon on the upper right corner of your HP Community profile, next to your profile name.

We're looking forward to helping you resolve this issue! 

Stay tuned, and thanks for your patience! 

Regards,