Ive always been getting the stutter and like Chicken I also think it might be sound related.
THe new patch seems smoother but I still get a slight stutter when I lift my ironsights in certain areas - as the sights come up, it feels like the game lags a little, as though its loading textures. Sometimes it doesn't happen, sometimes its not bad, but often its bad enough to make me miss my shot - very frustrating.
It also happens when firing the PPSh. Just tapping the trigger, the game stutters, which often leads to me dying. It happened with the MP40 the other day too. I saw a Russian, lifted and aimed, and held the trigger to give a long burst. Instead, there was a stutter, I fired only one round, he died and that was it - but I was still holding the mouse button down. So the stutter is affecting the control input as well.
It's really irritating. The game would be so much smoother and pleasurable to play if it wasnt for the stutter.