[randomguy]

I noticed it as well. Omnifocus is turning on the discrete GPU for me. It is odd, it only seems to do so when a specific action is performed, for example I can browse the lists of things in my inbox, but as soon as I click on the Menu (any of the menu entries) it immediately turns on the discrete GPU.

Not really a Mavericks issue, it was probably there before, but it is very evident with Mavericks as clicking on the battery/power icon highlights that Omnifocus is causing significant battery drain.

Also tried disable software update checking, didn't seem to help.