Posted by casper on
URL: https://www.es-forum.com/Turned-off-Laptop-still-emits-something-tp4035037p4035072.html

If it's a Lenovo laptop with a modern Intel chipset, it is very likely it has something called Intel AMT (Active Management Technology) inside it.

AMT is a small CPU inside the real CPU, that makes remote management of the computer possible. Depending on BIOS settings, this CPU may be running even with the power off. It is running, because it is supposed to be able to provide remote access, even to computers that are off (so that you can turn it on remotely).

https://en.wikipedia.org/wiki/Intel_Active_Management_Technology

I have an Lenovo P51, which is completely unusable otherwise because of extreme emissions, and the only way to get it to be silent on my AM radio because of this, was to pull the battery.

There is a setting somewhere in the BIOS, to make the AMT chip go to sleep also, but good luck finding it. It is not in the regular BIOS, but has to be accessed through a separate prompt, just before Windows loads.

There is also a feature in some Lenovo laptops, called "always on USB". This allows you to charge stuff through the USB port, even with the Laptop off. Check that always on USB is disabled in the BIOS, if you have that feature.

Besides the AMT and USB, I think others here came up with good ideas for the rest of the possibilities.