Firaxis and 2K aren't giving anything away about what the problem is or when a fix will land, though they do tell us that they're 'aware some players have experienced performance issues' and that they're looking into it. It's a damn shame, crossing the line from ultimately meaningless visual sacrifices into actively annoying slowness.
I'm far from alone, as a glance at the Steam forums, official boards or Reddit will very quickly reveal.
