New to me machine running 18.04 64 and dual start win7. Delighted as ever with Ubuntu, until last weekend updates. I noticed the elevated fan noise from the machine. On checking the 4 four processors seem to be taking turns in running up to 100% and back down again
Please report the problem as a bug by running this command on the machine in a terminal:
ubuntu-bug gnome-shell
and then we will be able to help you in Launchpad.net.
This site is not meant for general support, but Launchpad is.
Drop by one of our support channels and show one of our gurus there.
Lots of folks are picking up crypto-mining viruses. They suck up a lot of CPU…but they aren’t bugs. They’re malware.
They can help you file a useful bug report, if you have never done it before.