Congrats on the new card.
Stuttering is stuttering and, from everything I read on this forum, is not really related to fps. Your system is another example of someone having a much better system than me, yet there is stuttering.
It seemed to me from reading through the forum that textureloading is a much contributing factor to the stuttering problem.
Maybe someone else has a more expert explanation.
You may also be interested in a thread in the perfromance subforum titled "a nice article on gpu testing", it is long, it won't give you a solution but it is a really, really great read if you want to get some insight beyond fps.
I have lower fps, yet the game runs smoothly, no stuttering at all (knock on wood, don't want to jinx it

), over London I am in the 30s with settings high to medium.
So if texture loading is a culprit maybe, just to try it out, lower the textures from original to high. I would like to know if that does anything for you.
You may also want to use the search function and search for "ram drive", Ataros has made a post on how to reduce stuttering, maybe that will help.