Low on the priority list, but...
I've noticed a long delay when you first cast an ice spell after starting the game or loading a save.
I think it's loading the spell animation and/or textures from disk that might be the cause? I don't know.
Defragmentation of the install drive didn't alleviate the problem, but I was wondering if it was at all fixable?
Can the spell assets be loaded into RAM ahead of time, maybe?