It doesn’t matter what quality I put the game on (though lowest does cause them to happen slightly less frequently), I’ll be chugging along at a decent rate (40-60), and then I walk down some stairs at 10 or less. The animation catches up, and for another 30 seconds or so it goes along just fine. It doesn’t seem to be triggered by anything, I can walk into the Metrica Province fire elemental room and it’ll be just fine, jump off a rock and it drops framerate.
System specs:
Nvidia Geforce GT 555m
Intel Core i5 @ 2.4 GHz
6GB RAM