You're definitely playing the hard settings.

I know this may not make the game a delight for you, but you might consider dropping back to the default video settings, and setting your unit size to simply 'large' rather than 'huge.' I'm not a real expert at the technical aspects of the game's features AKA, audio, video, etc. But it's possible that you're just taxing your machine's video card a little too much and developing addressability problems.

Yes, I'm speculating. I am a programmer, but my professional expertise is in IBM mainframe programming and not PC or midtier applications like video games. But some things in the programming culture are the same across architectures. If you're running into performace problems, getting freaky occurances, or just plain stoppages, it just might mean that you've run out of core memory to address the open items in your current game. If you're using the finest most video expensive/detailed display settings along with huge unit sizes, you're asking alot of your machine.

Try dropping down your unit sizes a notch and switching back to the default video settings and see what happens.

The video features in M2TW are more sophisticated than RTW. I have a laptop that I'm playing the game on and I have 2 gig of memory, 512 meg of videocard memory with my Nvidia 7950 GTX, and a 2Ghz machine. So far, (knock on wood) I haven't had any performace problems. But I'm just getting into the game and haven't played out a campaign to 100 turns yet. I usually try to kick up my virtual memory settings to 2Gig as well, but haven't done that yet. (I love this machine!) Or, as the pizzaguy would say --->

Sorry, for all the techie talk. Give the lower unit setting a shot with default video settings. See what happens. I'll be routing for you.