I've also encountered this problem just recently when I moved from a MacBook Pro to a Windows 10 laptop. Evernote is sometimes fine but whenever I start editing a note, the fan kicks in, CPU use rises substantially, and I have to quit out if I don't want to go deaf. This is with a brand new Alienware laptop, so plenty of horsepower. Have no idea why Evernote is consuming that much of my CPU.
This problem is reproduceable as well. I think on laptops it's more noticeable because fan usage makes it quite obvious.