Interesting, I've had no issues with Sorawind personally. All characters have the run animation set to looping.
Just checked Sorawind and it's setup the same way.
I'm wondering if there are some GPU-related issues which are leaking into other parts of the game and causing stalls.
For instance, if there's a failure to properly stop the animation, then the game will perceive this as a process that needs to be finished before anything can proceed.