I have not noticed that it changes the order in which my pictures are sorted.
Having just updated iPhoto, I run 30 separate Libraries, all indexed by date. Each time i open one of these I find iPhoto doing a 'Faces' scan. And each time I try to use the Media Inspector in iWeb to put pictures into iWeb the column of pics flicks back up to the top ... I keep having a tug of war between where I want the pictures to be, and where iPhoto's desperation for completing its 'Faces' routine wants the pictures to be. Yup, I want my own choices as to how I organise my photos in iPhoto. aAny of my libraries do not have ant faces in them, so it is a waste of CPU time and RAM for this to be happening with these. We are 'allowed' to organise our photos in a lot of different ways... why can we not have this as just one way to view our collections, just as we can organise manually, or by date, or whatever. Why anyone should get so enthusiastic as Apple does about 'Faces' passes me by completely.
There is quite a lot of comment on this in the Apple forums in various places, but the universal is that there seems to be no way to turn this off, and this is badly needed. Has anyone got a hack that will allow me to turn this scanning off... certainly until such time as I might find that i have a use for it? At the moment it is just stopping me working properly.
I have notified Apple of this concern, but how long we will have to wait for a patch or an app update... who knows???