Tried on my work mac this morning and it absolutely flew up to 800MB I thought i was in luck, but no... got to 840MB and it dropped to 23 hours and now going between one and two days.
I contacted Apple about this and pointed them to this thread. So far they have only asked all canned response questions: Did you sign out and back in, restart, any errors, etc..
I replied and now waiting for another response.