As an alternative solution, I accessed the display settings on Windows 8.1 (Control Panel > Appearance and Personalization > Display) and set the Menu text size to 10 (on the section "Change only the text size"). Now Evernote is looking good on my full hd screen resolution. Update: After setting font size to 10, I set it to 9 again to see the differences and strangely the aspect ratio was kept.
Some issues with high resolution display also on a Thinkpad T440s with 1920x1080 screen resolution. Fonts inside notes are ok, but the application fonts are too small.