for some reason at random, my cities disappear.  now this was also happening in beta 2a as well. everything is fine at first, then for some odd reason my cities disappear.  i have to restart the game for them to reappear.  my area of influence outline is still there, and i can see smoke rising up from invisible chimneys.

i have the newest graphics drivers from ATI as well.  still a no go. here are my pc specs.

intel core 2 quad, 4 gigs of ram, ati radeon 4800 series graphics card, windows 7 64 ultimate.