Howdy!
With the latest patch, you are not just downloading and then installing. It’s restructuring the game files and installing, it may also lower download speeds or stop the download to do this periodically. This process can increase CPU usage greatly though as long as your system doesn’t have any Overheating or power supply issues due to your CPU being under heavy load it should be fine. Our goal is to help players who run into issues narrow them down and resolve them.
We offer more information about this Here and Here.
If you swapped out to another CPU it could be a power supply issue or settings issue.
Thank you!