I just got the game today for my 1.67 Ghz Powerbook (10.4.7, 1.5 GB RAM, 128 MB radeon 9700.) I thought my decent graphics card would save me, but that isn't the case.
Kdoran, I don't know if I just have higher performace expectations than you, but I have to say I'm dissapointed. It's giving me painful memories of running Warcraft III on my old 350 mhz iMac. Right now I'm playing a small map with 4 AIs. It's been really laggy from the start, and I am now at 450 B.C. Scrolling, zooming, etc is all slow. Scrolling is laggy enough so that I try to avoid it whenever I can. Movies are laggy. The cursor, however, is fine. It is playable, but barely. The good news is it's been about the same slowness since the beginning of the game, so hopefully it won't get any slower towards the endgame. In between turns is speedy, which I found suprising because I thought my limiting factor would be my weak CPU.
I've been running in a window with everything on low, 1024x768, except for improvement animations. I turned that off, but the speed improvement seems to be small. I did play the game very briefly in fullscreen and it seemed just as slow. I played the Call of Duty 2 demo the other day, and it played great on low settings, which makes this all the more frustrating.