Here's an observation which may (or may not) be useful to those of you who've mentioned Patch3beta performance issues (as I did).

I completed first campaign earlier today, soon after loading the patch (3rd try). Interestingly, as soon as I started a new campaign, game ran smooth as silk on campaign map. I wonder if something in the earlier save files was somehow conflicting with the patch, whereas a campaign started running Patch3beta doesn't have the same issues.

I suppose it could be simply because there's far fewer units and other complexities in a new game...which might help explain why some of us were having problems with Patch3beta while others were not.