I am experiencing the exact same issue - whenever I open Evernote, it starts consuming over 25% of my notebook's CPU, causing the fan to start running at high speed and making noise. As soon as I close Evernote, the CPU usage goes down and fan speed reduces.
It does not seem to be caused by Evernote indexing (except if Evernote is indexing permanently), since it never stops.
I do note that, as soon as I have Evernote open, the Task Manager indicates at least 7 processes running.
I have version: 126.96.36.19981 (307881) Public (CE Build ce-53.2.6641)
This is really irritating. It means I have to close Evernote and only open it when I need to use it, since otherwise the fan noise is very distracting.
Anybody with any ideas on what could be causing this?