Graphic problem with elder scrolls oblivion

I have this problem in my elder scrolls 4 (see video below):

you see the magic ? is like the magic had lag, instead of need a second to finish, with this problem need more time. Is a really pain in the ass.

this is the second time that happend to me. in the steam version. I think there is a problem with the cinematic, because the first that happend before i finish the main quest, so the final scene when martin becomes akathosh it took 20 minutes for that scene to finish.

Because of that, I started the game again. This time I finish de main quest, and the dls. Now i was playing with mods, but again, this problem appaers again.

Anyone could guess why is this happening? I try with previous saves but the same problem happens.