[Will]

Does it only happen when playing SEV? If it happens at any other time, I would worry about heat issues in your computer. Try playing a different game (I know, blasphemy) that uses up similar or more power, like the FPS-flavor-of-the-month demo. If it happens with that too, I would look into cleaning out any dust buildup that may be blocking airflow, or adding additional fans or coolers to improve temperature conditions.

Also try updating drivers for video, sound, etc., to rule out problems with buggy drivers making things go wonky.

As for a bug report, if you can reproduce it on a save, that would be most ideal. If not, describe under what conditions it happens (ie, during combat replays, in the system view, during turn processing, etc), and make as detailed a list of your main hardware as possible: processor family (core type and cache size included, if you know it), video card model, sound card model. If it really is a weird problem with the SEV code, then this will help track things down, especially if more people with same/similar hardware report the same problems.