I've had this problem for quite a while now, but it seems it keeps getting progressively worse with each patch.

As the title says, there seems to be a random hang up whenever II or an NPC uses a spell (of any kind).

Oddly, it seems to happen the most often when I'm outside (though I could have sworn I've had such lockups once or twice while indoors too)

Obviously, it's quite the problem when you get a whole load of necromancers or such. Hell, with the warzones mod I'd be LUCKY if I can get through the skrimish between the stormcloaks/whiterun guards and the necromancers/bandits by the ritual stone without it crashing.

Any ideas whats causing that?!

I have gotten a couple of locks ups when spells are cast. I think 3 times. Thing is, I have gone back to the same battle with what appears to be just as much magic flying around and it is all good the next time. So, it could just be when two certain spells are cast at the same time.

I have read, but not tried, that if you open the console with the Tilde, for about 10 seconds, the lock up goes away.

happens the same here... when the battle is just one or a small group of mages vs me.

When I enter a warzone of mages against people, it's almost always bound to happen, and I think it's gotten worse with every new game patch as I said (hardly ever happened with 1.3, happened somewhat often with 1.410 untill after a lot of uninstalling and reinstalling skyrim from scratch I FINALLY got it to happen rarely again, but by that time 1.4.27 came out and the whole thing started over again )

the console thing doesn't work, for the simple reason that you can't access the console during a lockup.

Nobody has any other ideas? Not necessarily warzone's fault since it happens even when i'm far away from any warzone.

Seems to crash 100% of the time when I dual-weild ice storm

my guess
if these crashes are due to spell casting, and not consistent, sometime it crash, sometime it's not
i would say its likely due to graphice related
have you try lower graphic details, play non-HD?