Oart

It seems it indeed has to do with displaying a note. When I checked my version (6.16.4.8094 (308094) Public (CE Build ce-58.1.6897)) via Help>About and have that pop up open, CPU drops immediately. Close that pop up by clicking OK and have your note upfront again, CPU climbs again right away (for me up until 40% even). Also have run my laptop for hours just in the hope it would have to do something with indexing, but after hours of high CPU I think I can conclude that's not the cause. Now playing with displaying different notes, and indeed, displaying note containing e-mail text only also lowers CPU consumption.