Windows 10: Windows Update 21H2: plugged in reduces CPU from 2.6GHz to 0.78 GHz

Hi, I have a laptop with intel CPUs that run at 2.6GHz. Then Windows updated and now it's all stuck at 0.78GHz when I plug in my charger, the full 3GHz when I have it unplugged. However unplugging and replugging doesn't fix the problem.Yes, I've changed power management settings. I've also checked the temperature using all combinations of software for it, and I'm not overheating if anything, the fact that unplugging it returns back to 3 GHz shows this issue completely. It's not a battery life issue either as my battery can sustain charge for over an hour.The shown number on Task Manager is a

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Help!!!! CPU operating at only 0.51 GHz

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Look at the Performance tab and at the bottom click Open Resource Monitor, check if you are seeing only 1 core out of the 2, 3 or 4 on the CPU. I get different speeds depending on the core, usually waiting a bit will step through the cores.

 

CPU stuck at 0.38 Ghz when charger is plugged in.

Thanks for your reply, unfortunately none of these suggestions changed anything and the CPU speed still immediately drops to 0.38 Ghz when I plug it in. Is there anything else I could try?

 

Help!!!! CPU operating at only 0.51 GHz


Can someone please help? Experiencing sluggish performance and could barely browse the web.

The CPU is operating between only 0.51 and 0.53 GHz. Normal operation for me is usually 1.17GHz - 1.30 GHz. This behavior is happening with or without the machine plugged in.

The machine is currently plugged in and battery is at 78%.
Also, this behavior started after moving up to Windows 10 from 8.1
Please help, any advice would be appreciated.