Go Away, Cortana
I never use Cortana, but there it sits in my task mangler, using a not insignificant percentage of cycles. Well, until now.
Winaero shows how to uninstall Cortana. Here is a mirror to the uninstall files, in case that page disappears. Basically, unzip into a dir, run the .cmd as administrator, let it do its work, and then reboot.